diff --git a/build-all-dc.sh b/build-all-dc.sh
index d3fae8cdc..5fb9ba051 100755
--- a/build-all-dc.sh
+++ b/build-all-dc.sh
@@ -12,5 +12,6 @@ docker-compose build judge
 docker-compose build changelog
 docker-compose build history-provider
 docker-compose build game-lobby
+docker-compose build color-chooser
 docker-compose build gateway
 docker-compose build kafkacat
diff --git a/build-all-local.sh b/build-all-local.sh
index f1c2a48a9..6f9f7a3f4 100755
--- a/build-all-local.sh
+++ b/build-all-local.sh
@@ -4,6 +4,7 @@ docker-compose build judge
 docker-compose build changelog
 docker-compose build history-provider
 docker-compose build game-lobby
+docker-compose build color-chooser
 docker-compose build kafkacat
 cd gateway && cargo clean && cd .. && docker-compose build gateway
 docker-compose build kafkacat
diff --git a/build-giant-dc.sh b/build-giant-dc.sh
index aef253600..e06778c65 100755
--- a/build-giant-dc.sh
+++ b/build-giant-dc.sh
@@ -3,6 +3,7 @@
 docker-compose -f dc-giant.yml build judge
 docker-compose -f dc-giant.yml build changelog
 docker-compose -f dc-giant.yml build game-lobby
+docker-compose -f dc-giant.yml build color-chooser
 docker-compose -f dc-giant.yml build history-provider
 docker-compose -f dc-giant.yml build kafkacat
 
diff --git a/color-chooser/Dockerfile b/color-chooser/Dockerfile
new file mode 100644
index 000000000..deebaa229
--- /dev/null
+++ b/color-chooser/Dockerfile
@@ -0,0 +1,11 @@
+FROM gradle
+
+RUN curl -O https://raw.githubusercontent.com/vishnubob/wait-for-it/master/wait-for-it.sh
+
+RUN chmod 755 wait-for-it.sh
+
+COPY . .
+
+RUN sh build.sh
+
+CMD ["sh", "run.sh"]
diff --git a/color-chooser/build.gradle b/color-chooser/build.gradle
new file mode 100644
index 000000000..fcc6161cf
--- /dev/null
+++ b/color-chooser/build.gradle
@@ -0,0 +1,61 @@
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.41'
+}
+
+group 'farm.terkwood'
+version '0.0.1'
+
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+mainClassName = 'ApplicationKt'
+
+defaultTasks 'run'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+}
+
+test { useJUnitPlatform() }
+ext.junitVersion = '5.4.2'
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    compile "org.jetbrains.kotlin:kotlin-reflect:1.3.0"
+
+    // JSON serialization
+    compile 'com.fasterxml.jackson.core:jackson-databind:2.9.7'
+    compile 'com.fasterxml.jackson.module:jackson-module-kotlin:2.9.7'
+
+    compile 'org.apache.kafka:kafka-streams:2.3.0'
+
+
+    testCompile "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testImplementation(
+            'org.assertj:assertj-core:3.12.2',
+            "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    )
+    testRuntime("org.junit.jupiter:junit-jupiter-engine:$junitVersion")
+    testCompile 'org.apache.kafka:kafka-streams-test-utils:2.3.0'
+    testCompile group: 'org.rocksdb', name: 'rocksdbjni', version: '6.0.1'
+
+
+}
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+
+// fat jar
+jar {
+    manifest { attributes 'Main-Class': 'ApplicationKt' }
+    from {
+        configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
+    }
+}
diff --git a/color-chooser/build.sh b/color-chooser/build.sh
new file mode 100644
index 000000000..9394be12b
--- /dev/null
+++ b/color-chooser/build.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+PROJ_NAME="bugout.color-chooser"
+
+rm -f ./build/libs/$PROJ_NAME*.jar
+gradle build
+cp ./build/libs/$PROJ_NAME*.jar $PROJ_NAME.jar
diff --git a/color-chooser/gradle.properties b/color-chooser/gradle.properties
new file mode 100644
index 000000000..29e08e8ca
--- /dev/null
+++ b/color-chooser/gradle.properties
@@ -0,0 +1 @@
+kotlin.code.style=official
\ No newline at end of file
diff --git a/color-chooser/gradle/wrapper/gradle-wrapper.jar b/color-chooser/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 000000000..87b738cbd
Binary files /dev/null and b/color-chooser/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/color-chooser/gradle/wrapper/gradle-wrapper.properties b/color-chooser/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 000000000..3b544c362
--- /dev/null
+++ b/color-chooser/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Tue Aug 20 11:01:53 EDT 2019
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-all.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
diff --git a/color-chooser/gradlew b/color-chooser/gradlew
new file mode 100755
index 000000000..af6708ff2
--- /dev/null
+++ b/color-chooser/gradlew
@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/color-chooser/gradlew.bat b/color-chooser/gradlew.bat
new file mode 100644
index 000000000..0f8d5937c
--- /dev/null
+++ b/color-chooser/gradlew.bat
@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/color-chooser/run.sh b/color-chooser/run.sh
new file mode 100644
index 000000000..66e8cddb3
--- /dev/null
+++ b/color-chooser/run.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+
+./wait-for-it.sh kafka:9092 -s -- sleep 16
+java -jar bugout.color-chooser.jar
diff --git a/color-chooser/settings.gradle b/color-chooser/settings.gradle
new file mode 100644
index 000000000..acf43a38f
--- /dev/null
+++ b/color-chooser/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'bugout.color-chooser'
+
diff --git a/color-chooser/src/main/kotlin/AggregatedPrefs.kt b/color-chooser/src/main/kotlin/AggregatedPrefs.kt
new file mode 100644
index 000000000..108a3ab1f
--- /dev/null
+++ b/color-chooser/src/main/kotlin/AggregatedPrefs.kt
@@ -0,0 +1,7 @@
+import serdes.jsonMapper
+
+class AggregatedPrefs {
+    var prefs: ArrayList <ClientGameColorPref> = arrayListOf()
+    fun add(p: ClientGameColorPref) = prefs.add(p)
+    fun asByteArray(): ByteArray = jsonMapper.writeValueAsBytes(this)
+}
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/Aliases.kt b/color-chooser/src/main/kotlin/Aliases.kt
new file mode 100644
index 000000000..b8e46e168
--- /dev/null
+++ b/color-chooser/src/main/kotlin/Aliases.kt
@@ -0,0 +1,6 @@
+import java.util.UUID
+
+
+typealias ClientId = UUID
+typealias GameId = UUID
+typealias EventId = UUID
diff --git a/color-chooser/src/main/kotlin/Application.kt b/color-chooser/src/main/kotlin/Application.kt
new file mode 100644
index 000000000..da5e530e7
--- /dev/null
+++ b/color-chooser/src/main/kotlin/Application.kt
@@ -0,0 +1,195 @@
+import org.apache.kafka.common.serialization.Serdes
+import org.apache.kafka.common.utils.Bytes
+import org.apache.kafka.streams.*
+import org.apache.kafka.streams.kstream.*
+import org.apache.kafka.streams.state.KeyValueStore
+import serdes.*
+import java.time.temporal.ChronoUnit
+import java.util.*
+
+fun main() {
+    TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+    Application("kafka:9092").process()
+}
+
+const val REQUIRED_PREFS = 2
+
+class Application(private val brokers: String) {
+    fun process() {
+        val topology = build()
+
+        println(topology.describe())
+
+        val props = Properties()
+        props[StreamsConfig.BOOTSTRAP_SERVERS_CONFIG] = brokers
+        props[StreamsConfig.APPLICATION_ID_CONFIG] = "bugout-color-chooser"
+        props[StreamsConfig.PROCESSING_GUARANTEE_CONFIG] = "exactly_once"
+
+        val streams = KafkaStreams(topology, props)
+        streams.start()
+    }
+
+
+    fun build(): Topology {
+        val streamsBuilder = StreamsBuilder()
+
+        buildGameColorPref(streamsBuilder)
+
+        val aggregated = aggregateColorPrefs(streamsBuilder)
+
+        val readyToChoose: KStream<GameId, AggregatedPrefs> =
+            aggregated.toStream()
+                .filter { _, agg -> agg.prefs.size == REQUIRED_PREFS }
+
+        readyToChoose.mapValues { agg ->
+            ColorsChosen.resolve(agg.prefs[0], agg.prefs[1])
+        }.mapValues { v ->
+            println("🎨          ${v.gameId.short()} COLRCHSN $v")
+            jsonMapper.writeValueAsString(v)
+        }.to(
+            Topics.COLORS_CHOSEN,
+            Produced.with(Serdes.UUID(), Serdes.String())
+        )
+
+        return streamsBuilder.build()
+    }
+
+
+    private fun buildGameColorPref(streamsBuilder: StreamsBuilder) {
+        val chooseColorPref: KStream<ClientId, ChooseColorPref> =
+            streamsBuilder.stream<UUID, String>(
+                Topics.CHOOSE_COLOR_PREF,
+                Consumed.with(Serdes.UUID(), Serdes.String())
+            )
+                .mapValues { v ->
+                    jsonMapper.readValue(
+                        v,
+                        ChooseColorPref::class.java
+                    )
+                }
+
+        val gameReady: KStream<GameId, GameReady> =
+            streamsBuilder.stream<UUID, String>(
+                Topics.GAME_READY,
+                Consumed.with(Serdes.UUID(), Serdes.String())
+            )
+                .mapValues { v ->
+                    jsonMapper.readValue(
+                        v,
+                        GameReady::class.java
+                    )
+                }
+
+        // generate  a ClientGameReady event for the first client
+        gameReady
+            .map { _, gr ->
+                KeyValue(
+                    gr.clients.first,
+                    ClientGameReady(gr.clients.first, gr.gameId)
+                )
+            }
+            .mapValues { cgr -> jsonMapper.writeValueAsString(cgr) }
+            .to(
+                Topics.CLIENT_GAME_READY,
+                Produced.with(Serdes.UUID(), Serdes.String())
+            )
+
+        // generate a ClientGameReady event for the second client
+        gameReady
+            .map { _, gr ->
+                KeyValue(
+                    gr.clients.second,
+                    ClientGameReady(gr.clients.second, gr.gameId)
+                )
+            }
+            .mapValues { cgr -> jsonMapper.writeValueAsString(cgr) }
+            .to(
+                Topics.CLIENT_GAME_READY,
+                Produced.with(Serdes.UUID(), Serdes.String())
+            )
+
+
+        val clientGameReady: KStream<ClientId, ClientGameReady> =
+            streamsBuilder.stream<UUID, String>(
+                Topics.CLIENT_GAME_READY,
+                Consumed.with(Serdes.UUID(), Serdes.String())
+            )
+                .mapValues { v ->
+                    jsonMapper.readValue(
+                        v,
+                        ClientGameReady::class.java
+                    )
+                }
+
+        val prefJoiner: ValueJoiner<ClientGameReady,
+                ChooseColorPref, ClientGameColorPref> =
+            ValueJoiner { leftValue: ClientGameReady,
+                          rightValue: ChooseColorPref ->
+                ClientGameColorPref(
+                    leftValue.clientId, leftValue.gameId,
+                    rightValue.colorPref
+                )
+            }
+
+
+        val clientGameColorPref: KStream<ClientId, ClientGameColorPref> =
+            clientGameReady.join(
+                chooseColorPref, prefJoiner,
+                JoinWindows.of(ChronoUnit.YEARS.duration),
+                Joined.with(
+                    Serdes.UUID(),
+                    Serdes.serdeFrom(
+                        ClientGameReadySer(),
+                        ClientGameReadyDes()
+                    ),
+                    Serdes.serdeFrom(ChooseColorPrefSer(), ChooseColorPrefDes())
+                )
+            )
+
+        val gameColorPref = clientGameColorPref
+            .map { _, gcp ->
+                KeyValue(
+                    gcp.gameId,
+                    gcp
+                )
+            }
+
+        // these will be used to aggregate prefs
+        gameColorPref.mapValues { v -> jsonMapper.writeValueAsString(v) }.to(
+            Topics.GAME_COLOR_PREF,
+            Produced.with(Serdes.UUID(), Serdes.String())
+        )
+
+    }
+
+
+    private fun aggregateColorPrefs(
+        streamsBuilder: StreamsBuilder
+    ): KTable<GameId, AggregatedPrefs> =
+        streamsBuilder
+            .stream<UUID, String>(
+                Topics.GAME_COLOR_PREF,
+                Consumed.with(Serdes.UUID(), Serdes.String())
+            ).groupByKey(Serialized.with(Serdes.UUID(), Serdes.String()))
+            .aggregate({ AggregatedPrefs() },
+                { _, p, allPrefs ->
+                    allPrefs.add(
+                        jsonMapper.readValue(
+                            p,
+                            ClientGameColorPref::class.java
+                        )
+                    )
+                    allPrefs
+                },
+                Materialized.`as`<UUID, AggregatedPrefs, KeyValueStore<Bytes, ByteArray>>(
+                    Topics.COLOR_PREFS_STORE
+                )
+                    .withKeySerde(Serdes.UUID())
+                    .withValueSerde(
+                        Serdes.serdeFrom(
+                            AggPrefSer(),
+                            AggPrefDes()
+                        )
+                    )
+            )
+}
diff --git a/color-chooser/src/main/kotlin/ChooseColorPref.kt b/color-chooser/src/main/kotlin/ChooseColorPref.kt
new file mode 100644
index 000000000..27b419ce3
--- /dev/null
+++ b/color-chooser/src/main/kotlin/ChooseColorPref.kt
@@ -0,0 +1,9 @@
+import serdes.jsonMapper
+
+/** A client's chosen color preference.  Keyed by client ID */
+data class ChooseColorPref(
+        val clientId: ClientId,
+        val colorPref: ColorPref
+){
+        fun asByteArray(): ByteArray = jsonMapper.writeValueAsBytes(this)
+}
diff --git a/color-chooser/src/main/kotlin/ClientGameColorPref.kt b/color-chooser/src/main/kotlin/ClientGameColorPref.kt
new file mode 100644
index 000000000..52a9871f4
--- /dev/null
+++ b/color-chooser/src/main/kotlin/ClientGameColorPref.kt
@@ -0,0 +1,6 @@
+import serdes.jsonMapper
+
+/** result of a join */
+data class ClientGameColorPref(val clientId: ClientId,
+                               val gameId: GameId,
+                               val colorPref: ColorPref)
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/ClientGameReady.kt b/color-chooser/src/main/kotlin/ClientGameReady.kt
new file mode 100644
index 000000000..715f1d89f
--- /dev/null
+++ b/color-chooser/src/main/kotlin/ClientGameReady.kt
@@ -0,0 +1,11 @@
+import serdes.jsonMapper
+
+/** Emitted downstream of GameReady.  Client ID is
+ * topic key.
+ */
+data class ClientGameReady (
+        val clientId: ClientId,
+        val gameId: GameId
+){
+        fun asByteArray(): ByteArray = jsonMapper.writeValueAsBytes(this)
+}
diff --git a/color-chooser/src/main/kotlin/ColorPref.kt b/color-chooser/src/main/kotlin/ColorPref.kt
new file mode 100644
index 000000000..64946ebf6
--- /dev/null
+++ b/color-chooser/src/main/kotlin/ColorPref.kt
@@ -0,0 +1,7 @@
+enum class ColorPref {
+    Black,
+    White,
+    Any
+}
+
+fun isAny(c : ColorPref): Boolean = c == ColorPref.Any
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/ColorsChosen.kt b/color-chooser/src/main/kotlin/ColorsChosen.kt
new file mode 100644
index 000000000..c59fdf5ce
--- /dev/null
+++ b/color-chooser/src/main/kotlin/ColorsChosen.kt
@@ -0,0 +1,62 @@
+import kotlin.random.Random
+
+data class ColorsChosen(val gameId: GameId, val black: ClientId, val white: ClientId) {
+
+    companion object {
+        fun resolve(first: ClientGameColorPref, second: ClientGameColorPref): ColorsChosen {
+            val noConflict: Boolean by lazy { first.colorPref != second.colorPref }
+            val bf: ColorsChosen by lazy { blackFirst(first, second) }
+            val wf: ColorsChosen by lazy { whiteFirst(first, second) }
+            return when {
+                isAny(first.colorPref) ->
+                    when (force(second.colorPref)) {
+                        Color.Black -> wf
+                        Color.White -> bf
+                    }
+                isAny(second.colorPref) ->
+                    when (force(first.colorPref)) {
+                        Color.Black -> bf
+                        Color.White -> wf
+                    }
+                first.colorPref == ColorPref.Black && noConflict -> 
+                    bf
+                first.colorPref == ColorPref.White && noConflict ->
+                    wf
+                // both sides picked the same color
+                else ->
+                    when (random()) {
+                        Color.Black -> blackFirst(first, second)
+                        Color.White -> whiteFirst(first, second)
+                    }
+            }
+        }
+
+        private fun blackFirst(first: ClientGameColorPref, second: ClientGameColorPref) =
+            ColorsChosen(
+                gameId = first.gameId,
+                black = first.clientId,
+                white = second.clientId
+            )
+
+        private fun whiteFirst(first: ClientGameColorPref, second: ClientGameColorPref) =
+            ColorsChosen(
+                gameId = first.gameId,
+                black = second.clientId,
+                white = first.clientId
+            )
+
+        private fun random(): Color = when (Random.nextBoolean()) {
+            false -> Color.Black
+            true -> Color.White
+        }
+
+        private fun force(cp: ColorPref): Color =
+            when (cp) {
+                ColorPref.Any -> random()
+                ColorPref.Black -> Color.Black
+                ColorPref.White -> Color.White
+            }
+    }
+}
+
+enum class Color { Black, White }
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/GameColorPref.kt b/color-chooser/src/main/kotlin/GameColorPref.kt
new file mode 100644
index 000000000..09493ce6f
--- /dev/null
+++ b/color-chooser/src/main/kotlin/GameColorPref.kt
@@ -0,0 +1,12 @@
+/** Represents an individual client's color
+ * preference for a specific game.  Used in
+ * multiple contexts:  initially, this can
+ * be keyed by client ID as the result of
+ * a join against ClientGameReady
+ *
+ * This can also be an input to the topic
+ * which aggregates color prefs for a given
+ * game
+ */
+data class GameColorPref (val clientId: ClientId, val gameId: GameId,
+                          val colorPref: ColorPref)
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/GameReady.kt b/color-chooser/src/main/kotlin/GameReady.kt
new file mode 100644
index 000000000..d653546a2
--- /dev/null
+++ b/color-chooser/src/main/kotlin/GameReady.kt
@@ -0,0 +1,4 @@
+/** emitted by game-lobby */
+data class GameReady(val gameId: GameId,
+                     val clients: Pair<ClientId, ClientId>,
+                     val eventId: EventId)
diff --git a/color-chooser/src/main/kotlin/Topics.kt b/color-chooser/src/main/kotlin/Topics.kt
new file mode 100644
index 000000000..f8552ebf8
--- /dev/null
+++ b/color-chooser/src/main/kotlin/Topics.kt
@@ -0,0 +1,8 @@
+object Topics {
+    const val CHOOSE_COLOR_PREF = "bugout-choose-color-pref-cmd"
+    const val GAME_READY = "bugout-game-ready-ev"
+    const val CLIENT_GAME_READY = "bugout-client-game-ready-ev"
+    const val GAME_COLOR_PREF = "bugout-game-color-pref-ev"
+    const val COLOR_PREFS_STORE = "bugout-color-prefs-store"
+    const val COLORS_CHOSEN = "bugout-colors-chosen-ev"
+}
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/serdes/AggPrefSerde.kt b/color-chooser/src/main/kotlin/serdes/AggPrefSerde.kt
new file mode 100644
index 000000000..7c7ee2cb3
--- /dev/null
+++ b/color-chooser/src/main/kotlin/serdes/AggPrefSerde.kt
@@ -0,0 +1,32 @@
+package serdes
+
+import AggregatedPrefs
+import com.fasterxml.jackson.core.type.TypeReference
+
+import org.apache.kafka.common.errors.SerializationException
+import org.apache.kafka.common.serialization.Deserializer
+import org.apache.kafka.common.serialization.Serializer
+import java.lang.RuntimeException
+
+class AggPrefSer : Serializer<AggregatedPrefs> {
+    override fun serialize(topic: String?, data: AggregatedPrefs?): ByteArray? {
+        if (data == null) {return null}
+
+        try {return data.asByteArray()}catch(e: RuntimeException) {
+            throw SerializationException("error serializing aggregated prefs", e)
+        }
+    }
+}
+
+class AggPrefDes : Deserializer<AggregatedPrefs> {
+    override fun deserialize(topic: String?, data: ByteArray?): AggregatedPrefs? {
+        if (data == null) {return null}
+
+        try {
+            return jsonMapper.readValue(data, AggregatedPrefs::class.java)
+        } catch (e: RuntimeException) {
+            throw SerializationException("error deserializing aggregated prefs", e)
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/serdes/ChooseColorPrefDes.kt b/color-chooser/src/main/kotlin/serdes/ChooseColorPrefDes.kt
new file mode 100644
index 000000000..19cd76915
--- /dev/null
+++ b/color-chooser/src/main/kotlin/serdes/ChooseColorPrefDes.kt
@@ -0,0 +1,26 @@
+package serdes
+
+import ChooseColorPref
+import org.apache.kafka.common.errors.SerializationException
+import org.apache.kafka.common.serialization.Deserializer
+
+class ChooseColorPrefDes : Deserializer<ChooseColorPref> {
+
+    override fun configure(configs: Map<String, *>, isKey: Boolean) {}
+
+    override fun close() {}
+
+    override fun deserialize(topic: String, bytes: ByteArray?): ChooseColorPref? {
+        if (bytes == null) {
+            return null
+        }
+
+        try {
+            return jsonMapper.readValue(bytes, ChooseColorPref::class.java)
+        } catch (e: RuntimeException) {
+            throw SerializationException("Error deserializing value", e)
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/serdes/ChooseColorPrefSer.kt b/color-chooser/src/main/kotlin/serdes/ChooseColorPrefSer.kt
new file mode 100644
index 000000000..4a9904b34
--- /dev/null
+++ b/color-chooser/src/main/kotlin/serdes/ChooseColorPrefSer.kt
@@ -0,0 +1,28 @@
+package serdes
+
+
+import ChooseColorPref
+import org.apache.kafka.common.errors.SerializationException
+import org.apache.kafka.common.serialization.Serializer
+
+
+class ChooseColorPrefSer : Serializer<ChooseColorPref> {
+
+    override fun configure(configs: Map<String, *>, isKey: Boolean) {}
+
+    override fun close() {}
+
+    override fun serialize(topic: String, logAgg: ChooseColorPref?): ByteArray? {
+        if (logAgg == null) {
+            return null
+        }
+
+        try {
+            return logAgg.asByteArray()
+        } catch (e: RuntimeException) {
+            throw SerializationException("Error serializing value", e)
+        }
+
+    }
+
+}
diff --git a/color-chooser/src/main/kotlin/serdes/ClientGameReadyDes.kt b/color-chooser/src/main/kotlin/serdes/ClientGameReadyDes.kt
new file mode 100644
index 000000000..c7c1e9f0f
--- /dev/null
+++ b/color-chooser/src/main/kotlin/serdes/ClientGameReadyDes.kt
@@ -0,0 +1,29 @@
+package serdes
+
+
+import ClientGameReady
+import org.apache.kafka.common.errors.SerializationException
+import org.apache.kafka.common.serialization.Deserializer
+
+class ClientGameReadyDes : Deserializer<ClientGameReady> {
+
+    override fun configure(configs: Map<String, *>, isKey: Boolean) {}
+
+    override fun close() {}
+
+    override fun deserialize(topic: String, bytes: ByteArray?): ClientGameReady? {
+        if (bytes == null) {
+            return null
+        }
+
+        try {
+            return jsonMapper.readValue(bytes, ClientGameReady::class.java)
+        } catch (e: RuntimeException) {
+            throw SerializationException("Error deserializing value", e)
+        }
+
+    }
+
+}
+
+
diff --git a/color-chooser/src/main/kotlin/serdes/ClientGameReadySer.kt b/color-chooser/src/main/kotlin/serdes/ClientGameReadySer.kt
new file mode 100644
index 000000000..2cc1f0903
--- /dev/null
+++ b/color-chooser/src/main/kotlin/serdes/ClientGameReadySer.kt
@@ -0,0 +1,26 @@
+package serdes
+
+import ClientGameReady
+import org.apache.kafka.common.errors.SerializationException
+import org.apache.kafka.common.serialization.Serializer
+
+class ClientGameReadySer : Serializer<ClientGameReady> {
+
+    override fun configure(configs: Map<String, *>, isKey: Boolean) {}
+
+    override fun close() {}
+
+    override fun serialize(topic: String, data: ClientGameReady?): ByteArray? {
+        if (data == null) {
+            return null
+        }
+
+        try {
+            return data.asByteArray()
+        } catch (e: RuntimeException) {
+            throw SerializationException("Error serializing value", e)
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/color-chooser/src/main/kotlin/serdes/jsonMapper.kt b/color-chooser/src/main/kotlin/serdes/jsonMapper.kt
new file mode 100644
index 000000000..612c5bee7
--- /dev/null
+++ b/color-chooser/src/main/kotlin/serdes/jsonMapper.kt
@@ -0,0 +1,14 @@
+package serdes
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.databind.SerializationFeature
+import com.fasterxml.jackson.databind.util.StdDateFormat
+import com.fasterxml.jackson.module.kotlin.registerKotlinModule
+
+
+val jsonMapper = ObjectMapper().apply {
+    registerKotlinModule()
+    disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
+    dateFormat = StdDateFormat()
+}
+
diff --git a/color-chooser/src/main/kotlin/shortUuid.kt b/color-chooser/src/main/kotlin/shortUuid.kt
new file mode 100644
index 000000000..d3605009e
--- /dev/null
+++ b/color-chooser/src/main/kotlin/shortUuid.kt
@@ -0,0 +1,4 @@
+import java.util.*
+
+const val SIZE = 8
+fun UUID.short(): String = this.toString().take(SIZE)
diff --git a/color-chooser/src/test/kotlin/Setup.kt b/color-chooser/src/test/kotlin/Setup.kt
new file mode 100644
index 000000000..c421421a0
--- /dev/null
+++ b/color-chooser/src/test/kotlin/Setup.kt
@@ -0,0 +1,17 @@
+import org.apache.kafka.common.serialization.Serdes
+import org.apache.kafka.streams.StreamsConfig
+import org.apache.kafka.streams.TopologyTestDriver
+import java.util.*
+
+fun setup(): TopologyTestDriver {
+    // setup test driver
+    val props = Properties()
+    props[StreamsConfig.BOOTSTRAP_SERVERS_CONFIG] = "no-matter"
+    props[StreamsConfig.APPLICATION_ID_CONFIG] = "test-bugout-color-chooser"
+    props[StreamsConfig.PROCESSING_GUARANTEE_CONFIG] = "exactly_once"
+
+
+    val topology = Application("dummy-brokers").build()
+    println(topology.describe())
+    return TopologyTestDriver(topology, props)
+}
\ No newline at end of file
diff --git a/color-chooser/src/test/kotlin/TestChoice.kt b/color-chooser/src/test/kotlin/TestChoice.kt
new file mode 100644
index 000000000..0499419f3
--- /dev/null
+++ b/color-chooser/src/test/kotlin/TestChoice.kt
@@ -0,0 +1,226 @@
+import org.apache.kafka.clients.producer.ProducerRecord
+import org.apache.kafka.common.serialization.*
+import org.apache.kafka.streams.TopologyTestDriver
+import org.apache.kafka.streams.test.ConsumerRecordFactory
+import org.apache.kafka.streams.test.OutputVerifier
+import org.junit.jupiter.api.*
+import serdes.jsonMapper
+import java.util.*
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestChoice {
+    private val testDriver: TopologyTestDriver = setup()
+
+    private fun push(
+        c1: ChooseColorPref,
+        c2: ChooseColorPref,
+        gameId: GameId
+    ): ProducerRecord<UUID, String>? {
+
+        val gameReadyEvent = GameReady(
+            gameId,
+            Pair(c1.clientId, c2.clientId),
+            eventId = UUID.randomUUID()
+        )
+
+        val factory =
+            ConsumerRecordFactory(
+                UUIDSerializer(), StringSerializer()
+            )
+
+
+        testDriver.pipeInput(
+            factory.create(
+                Topics.CHOOSE_COLOR_PREF,
+                c1.clientId,
+                jsonMapper.writeValueAsString(c1)
+            )
+        )
+
+        testDriver.pipeInput(
+            factory.create(
+                Topics.CHOOSE_COLOR_PREF,
+                c2.clientId,
+                jsonMapper.writeValueAsString(c2)
+            )
+        )
+
+
+        testDriver.pipeInput(
+            factory.create(
+                Topics.GAME_READY,
+                gameId,
+                jsonMapper.writeValueAsString(gameReadyEvent)
+            )
+        )
+
+        return testDriver.readOutput(
+            Topics.COLORS_CHOSEN,
+            UUIDDeserializer(),
+            StringDeserializer()
+        )
+
+
+    }
+
+    @Test
+    fun testNoConflict() {
+
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val c1Pref = ChooseColorPref(clientOne, ColorPref.White)
+        val c2Pref = ChooseColorPref(clientTwo, ColorPref.Black)
+
+        val chosen = push(
+            c1Pref,
+            c2Pref, gameId
+        )
+
+
+        OutputVerifier.compareKeyValue(
+            chosen, gameId,
+            jsonMapper.writeValueAsString(
+                ColorsChosen(
+                    gameId = gameId,
+                    black = clientTwo,
+                    white = clientOne
+                )
+            )
+        )
+    }
+
+    @Test
+    fun testAnotherNoConflict() {
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val chosen = push(
+            ChooseColorPref(clientOne, ColorPref.Black),
+            ChooseColorPref(clientTwo, ColorPref.White), gameId
+        )
+
+        OutputVerifier.compareKeyValue(
+            chosen, gameId,
+            jsonMapper.writeValueAsString(
+                ColorsChosen(
+                    gameId = gameId,
+                    black = clientOne,
+                    white = clientTwo
+                )
+            )
+        )
+    }
+
+    @Test
+    fun testConflict() {
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val chosen: ColorsChosen = jsonMapper.readValue(push(
+            ChooseColorPref(clientOne, ColorPref.Black),
+            ChooseColorPref(clientTwo, ColorPref.Black), gameId
+        )?.value(), ColorsChosen::class.java)
+
+        Assertions.assertTrue(when (chosen.black) {
+            clientOne -> chosen.white == clientTwo
+            else -> chosen.black == clientTwo && chosen.white == clientOne
+        })
+    }
+
+    @Test
+    fun testMoreConflict() {
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val chosen: ColorsChosen = jsonMapper.readValue(push(
+            ChooseColorPref(clientOne, ColorPref.White),
+            ChooseColorPref(clientTwo, ColorPref.White), gameId
+        )?.value(), ColorsChosen::class.java)
+
+        Assertions.assertTrue(when (chosen.black) {
+            clientOne -> chosen.white == clientTwo
+            else -> chosen.black == clientTwo && chosen.white == clientOne
+        })
+    }
+
+    @Test
+    fun testSimpleDemands() {
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val chosen = push(
+            ChooseColorPref(clientOne, ColorPref.Any),
+            ChooseColorPref(clientTwo, ColorPref.White), gameId
+        )
+
+        OutputVerifier.compareKeyValue(
+            chosen, gameId,
+            jsonMapper.writeValueAsString(
+                ColorsChosen(
+                    gameId = gameId,
+                    black = clientOne,
+                    white = clientTwo
+                )
+            )
+        )
+    }
+
+    @Test
+    fun testMoreDemands() {
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val chosen = push(
+            ChooseColorPref(clientOne, ColorPref.White),
+            ChooseColorPref(clientTwo, ColorPref.Any), gameId
+        )
+
+        OutputVerifier.compareKeyValue(
+            chosen, gameId,
+            jsonMapper.writeValueAsString(
+                ColorsChosen(
+                    gameId = gameId,
+                    black = clientTwo,
+                    white = clientOne
+                )
+            )
+        )
+    }
+
+    @Test
+    fun testLooseConcerns() {
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val chosenJson = push(
+            ChooseColorPref(clientOne, ColorPref.Any),
+            ChooseColorPref(clientTwo, ColorPref.Any), gameId
+        )
+
+        val chosen: ColorsChosen =
+            jsonMapper.readValue(chosenJson?.value(), ColorsChosen::class.java)
+
+        when (chosen.black) {
+            clientOne -> Assertions.assertTrue(chosen.white == clientTwo)
+            else -> Assertions.assertTrue(
+                chosen.black == clientTwo &&
+                        chosen.white == clientOne
+            )
+        }
+
+    }
+
+
+    @AfterAll
+    fun tearDown() {
+        testDriver.close()
+    }
+}
\ No newline at end of file
diff --git a/color-chooser/src/test/kotlin/TestJoin.kt b/color-chooser/src/test/kotlin/TestJoin.kt
new file mode 100644
index 000000000..a586bef37
--- /dev/null
+++ b/color-chooser/src/test/kotlin/TestJoin.kt
@@ -0,0 +1,92 @@
+import org.apache.kafka.common.serialization.*
+import org.apache.kafka.streams.TopologyTestDriver
+import org.apache.kafka.streams.test.ConsumerRecordFactory
+import org.junit.jupiter.api.*
+import serdes.jsonMapper
+import java.util.*
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestJoin {
+    private val testDriver: TopologyTestDriver = setup()
+
+    @Test
+    fun testJoin() {
+
+        val clientOne = UUID.randomUUID()
+        val clientTwo = UUID.randomUUID()
+        val gameId = UUID.randomUUID()
+
+        val clientOnePref = ChooseColorPref(clientOne, ColorPref.Black)
+        val clientTwoPref = ChooseColorPref(clientTwo, ColorPref.White)
+
+        val gameReadyEvent = GameReady(gameId, Pair(clientOne, clientTwo), eventId = UUID.randomUUID())
+
+        val factory =
+            ConsumerRecordFactory(
+                UUIDSerializer(), StringSerializer()
+            )
+
+
+        testDriver.pipeInput(
+            factory.create(
+                Topics.CHOOSE_COLOR_PREF,
+                clientOne,
+                jsonMapper.writeValueAsString(clientOnePref)
+            )
+        )
+
+        testDriver.pipeInput(
+            factory.create(
+                Topics.CHOOSE_COLOR_PREF,
+                clientTwo,
+                jsonMapper.writeValueAsString(clientTwoPref)
+            )
+        )
+
+
+        testDriver.pipeInput(
+            factory.create(
+                Topics.GAME_READY,
+                gameId,
+                jsonMapper.writeValueAsString(gameReadyEvent)
+            )
+        )
+
+
+        val gcpOne =
+            testDriver.readOutput(
+                Topics.GAME_COLOR_PREF,
+                UUIDDeserializer(),
+                StringDeserializer()
+            )
+
+
+        val gcpTwo =
+            testDriver.readOutput(
+                Topics.GAME_COLOR_PREF,
+                UUIDDeserializer(),
+                StringDeserializer()
+            )
+
+
+        val gameColorPrefs =
+            listOf(gcpOne.value(), gcpTwo.value())
+                .map { jsonMapper.readValue(it, GameColorPref::class.java) }
+
+        val expectedSize = 2
+        Assertions.assertEquals(expectedSize,
+            gameColorPrefs.size)
+
+        Assertions.assertArrayEquals(
+            listOf(
+                GameColorPref(clientOne,gameId,clientOnePref.colorPref),
+                GameColorPref(clientTwo,gameId,clientTwoPref.colorPref)
+            ).toTypedArray(),
+            gameColorPrefs.toTypedArray())
+    }
+
+    @AfterAll
+    fun tearDown() {
+        testDriver.close()
+    }
+}
\ No newline at end of file
diff --git a/color-chooser/topology.jpg b/color-chooser/topology.jpg
new file mode 100644
index 000000000..88069b789
Binary files /dev/null and b/color-chooser/topology.jpg differ
diff --git a/dc-giant.yml b/dc-giant.yml
index 6507686c5..3ffa5c6aa 100644
--- a/dc-giant.yml
+++ b/dc-giant.yml
@@ -12,7 +12,7 @@ services:
       KAFKA_ADVERTISED_HOST_NAME: kafka
       KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092
       KAFKA_LISTENERS: PLAINTEXT://0.0.0.0:9092
-      KAFKA_CREATE_TOPICS: "bugout-move-accepted-ev:1:1,bugout-move-made-ev:1:1,bugout-move-rejected-ev:1:1,bugout-make-move-cmd:1:1,bugout-game-states:1:1,bugout-provide-history-cmd:1:1,bugout-history-provided-ev:1:1,bugout-find-public-game-cmd:1:1,bugout-create-game-cmd:1:1,bugout-wait-for-opponent-ev:1:1,bugout-game-ready-ev:1:1,bugout-private-game-rejected-ev:1:1,bugout-join-private-game-cmd:1:1,bugout-game-lobby-commands:1:1"
+      KAFKA_CREATE_TOPICS: "bugout-move-accepted-ev:1:1,bugout-move-made-ev:1:1,bugout-move-rejected-ev:1:1,bugout-make-move-cmd:1:1,bugout-game-states:1:1,bugout-provide-history-cmd:1:1,bugout-history-provided-ev:1:1,bugout-find-public-game-cmd:1:1,bugout-create-game-cmd:1:1,bugout-wait-for-opponent-ev:1:1,bugout-game-ready-ev:1:1,bugout-private-game-rejected-ev:1:1,bugout-join-private-game-cmd:1:1,bugout-game-lobby-commands:1:1,bugout-choose-color-pref-cmd:1:1,bugout-client-game-ready-ev:1:1,bugout-game-color-pref-ev:1:1,bugout-colors-chosen-ev:1:1"
       KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
@@ -40,6 +40,12 @@ services:
       - "kafka"
     depends_on:
       - "kafka"
+  color-chooser:
+    build: color-chooser/.
+    links:
+      - "kafka"
+    depends_on:
+      - "kafka"
   startup:
     build: startup/.
     links:
diff --git a/docker-compose.yml b/docker-compose.yml
index bfd352638..934c011ba 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -12,7 +12,7 @@ services:
       KAFKA_ADVERTISED_HOST_NAME: kafka
       KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092
       KAFKA_LISTENERS: PLAINTEXT://0.0.0.0:9092
-      KAFKA_CREATE_TOPICS: "bugout-move-accepted-ev:1:1,bugout-move-made-ev:1:1,bugout-move-rejected-ev:1:1,bugout-make-move-cmd:1:1,bugout-game-states:1:1,bugout-provide-history-cmd:1:1,bugout-history-provided-ev:1:1,bugout-find-public-game-cmd:1:1,bugout-create-game-cmd:1:1,bugout-wait-for-opponent-ev:1:1,bugout-game-ready-ev:1:1,bugout-private-game-rejected-ev:1:1,bugout-join-private-game-cmd:1:1,bugout-game-lobby-commands:1:1"
+      KAFKA_CREATE_TOPICS: "bugout-move-accepted-ev:1:1,bugout-move-made-ev:1:1,bugout-move-rejected-ev:1:1,bugout-make-move-cmd:1:1,bugout-game-states:1:1,bugout-provide-history-cmd:1:1,bugout-history-provided-ev:1:1,bugout-find-public-game-cmd:1:1,bugout-create-game-cmd:1:1,bugout-wait-for-opponent-ev:1:1,bugout-game-ready-ev:1:1,bugout-private-game-rejected-ev:1:1,bugout-join-private-game-cmd:1:1,bugout-game-lobby-commands:1:1,bugout-choose-color-pref-cmd:1:1,bugout-client-game-ready-ev:1:1,bugout-game-color-pref-ev:1:1,bugout-colors-chosen-ev:1:1"
       KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
@@ -56,6 +56,12 @@ services:
       - "kafka"
     depends_on:
       - "kafka"
+  color-chooser:
+    build: color-chooser/.
+    links:
+      - "kafka"
+    depends_on:
+      - "kafka"
   startup:
     build: startup/.
     links:
diff --git a/game-lobby/gradle/wrapper/gradle-wrapper.properties b/game-lobby/gradle/wrapper/gradle-wrapper.properties
index 44e7c4d1d..d1bcfc0a0 100644
--- a/game-lobby/gradle/wrapper/gradle-wrapper.properties
+++ b/game-lobby/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,6 @@
+#Mon Aug 19 06:42:51 EDT 2019
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-all.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-bin.zip
-zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
diff --git a/kafkacat/color-chooser.sh b/kafkacat/color-chooser.sh
new file mode 100644
index 000000000..9882d04be
--- /dev/null
+++ b/kafkacat/color-chooser.sh
@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# need a gameready event to have been emitted by game lobby
+# keyed by game ID
+echo 'ffff0000-bbab-bbbb-5434-b63e326006bd:{"gameId":"ffff0000-bbab-bbbb-5434-b63e326006bd", "clients": {"first":"eeeeeeee-fefe-1234-ffff-d5f736841a5f","second":"bbbbbbbb-8787-6a6a-5432-bce65874eed2"}, "eventId":"3f1eac1e-ed30-4fdf-811a-eaf9eba01cc5"}' | kafkacat -b kafka:9092 -t bugout-game-ready-ev -K: -P
+
+
+# each player chooses a color pref
+# keyed by client ID
+echo 'eeeeeeee-fefe-1234-ffff-d5f736841a5f:{"clientId":"eeeeeeee-fefe-1234-ffff-d5f736841a5f", "colorPref":"Black"}' | kafkacat -b kafka:9092 -t bugout-choose-color-pref-cmd -K: -P
+echo 'bbbbbbbb-8787-6a6a-5432-bce65874eed2:{"clientId":"bbbbbbbb-8787-6a6a-5432-bce65874eed2", "colorPref":"Black"}' | kafkacat -b kafka:9092 -t bugout-choose-color-pref-cmd -K: -P
+
+
+# wait for the magic to happen
+# keyed by game ID
+kafkacat -b kafka:9092 -t bugout-colors-chosen-ev -C -K: