diff --git a/index.html b/index.html
index 9efadb5..329c040 100644
--- a/index.html
+++ b/index.html
@@ -9,6 +9,7 @@
   <script type="text/javascript" src="js/dep/es5-shim.js"></script>
   <script type="text/javascript" src="js/lib/grid.js"></script>
   <script type="text/javascript" src="js/lib/game.js"></script>
+  <script type="text/javascript" src="js/lib/instructions.js"></script>
   <script type="text/javascript" src="js/lib/visualizer.js"></script>
   <script type="text/javascript" src="js/lib/program.js"></script>
   <script type="text/javascript" src="js/lib/robot.js"></script>
diff --git a/js/lib/game.js b/js/lib/game.js
index d510c70..190282a 100644
--- a/js/lib/game.js
+++ b/js/lib/game.js
@@ -52,12 +52,18 @@ Game.prototype._getRobot = function(a, b) {
   return this._cells[a][b];
 };
 
+Game.prototype._removeRobot = function(a, b) {
+  this._cells[a][b] = null;
+};
+
 Game.prototype._setRobot = function(a, b, robot) {
   this._cells[a][b] = robot;
   robot.setCoordinates(a, b);
 };
 
 Game.prototype.kill = function(robot) {
+  var coordinates = robot.getCoordinates();
+  this._removeRobot(coordinates.a, coordinates.b);
   var index = this._robots.indexOf(robot);
   this._robots.splice(index, 1);
   this.emit('death', robot);
@@ -75,7 +81,7 @@ Game.prototype.isFirstStep = function() {
   return this._step === 1;
 };
 
-Game.prototype.nextStep = function() {
+Game.prototype.nextTick = function() {
   this._step++;
 
   if (this.isFirstStep()) {
@@ -83,8 +89,9 @@ Game.prototype.nextStep = function() {
     return;
   }
 
+  var self = this;
   this.getRobots().forEach(function(robot) {
-    robot.nextStep();
+    robot.nextTick();
   });
 };
 
diff --git a/js/lib/instructions.js b/js/lib/instructions.js
index 78d72d7..d73a18b 100644
--- a/js/lib/instructions.js
+++ b/js/lib/instructions.js
@@ -1,20 +1,62 @@
-module.exports = {
+var instructions = {
+  'init': {
+    costs: 0,
+    execute: function(game, robot, args) {}
+  },
   'rotate': {
     costs: 1,
     execute: function(game, robot, args) {
       robot.rotate(args[0]);
-      return args;
+    }
+  },
+  'move': {
+    costs: 1,
+    execute: function(game, robot, args) {
+      robot.move();
+    }
+  },
+  'scan': {
+    costs: 1,
+    execute: function(game, robot, args) {
+      var coordinates = game._getCoordinatesInFrontOf(robot);
+      var otherRobot = game._getRobot(coordinates.a, coordinates.b);
+      if (!otherRobot) {
+        return ['empty'];
+      }
+
+      return (otherRobot.getPlayer() === robot.getPlayer())
+        ? 'friend'
+        : 'enemy';
     }
   },
   'transfer': {
     costs: function(game, robot, args) {
+      return 1;
     },
-    execute: function() {
+    execute: function(game, robot, args) {
+      var coordinates = game._getCoordinatesInFrontOf(robot);
+      var otherRobot = game._getRobot(coordinates.a, coordinates.b);
+      if (!otherRobot) {
+        return;
+      }
+
+      var sourceProgram = robot._code[args[0]];
+      otherRobot._code = $.extend(true, {}, otherRobot._code);
+
+      var destProgram = {};
+      otherRobot._code[otherRobot._currentProgram] = destProgram;
+      for (var key in sourceProgram) {
+        destProgram[key] = sourceProgram[key];
+      }
+
+      otherRobot._currentArgs = [];
+      otherRobot._currentInstruction = 'init';
+      otherRobot._remainingCycles = 0;
     },
   },
   'build': {
     costs: function(game, robot, args) {
-      return 10;
+      return 2;
       //if (args[0] === 'builder') {
         //return 10;
       //}
@@ -26,7 +68,7 @@ module.exports = {
       //return new Error('build: unknown type: ' + args[0]);
     },
     execute: function(game, robot, args) {
-      var coordinates = game.getCoordinatesInFrontOf(robot);
+      game.buildRobot(robot);
     },
   }
 };
diff --git a/js/lib/robot.js b/js/lib/robot.js
index 38e7616..f4b8985 100644
--- a/js/lib/robot.js
+++ b/js/lib/robot.js
@@ -2,7 +2,11 @@ function Robot() {
   this._a = null;
   this._b = null;
   this._rotation = null;
-  this._operation = null;
+
+  this._currentProgram = 'main';
+  this._currentArgs = [];
+  this._currentInstruction = 'init';
+  this._remainingCycles = 0;
 
   this._code = null;
   this._game = null;
@@ -62,6 +66,21 @@ Robot.prototype.rotate = function(direction) {
   this._game.emit('rotate', this);
 };
 
+Robot.prototype.move = function() {
+  var newCoordinates = this._game._getCoordinatesInFrontOf(this);
+  if (this._game._getRobot(newCoordinates.a, newCoordinates.b)) {
+    return;
+  }
+
+  var oldCoordinates = this.getCoordinates();
+  this.setCoordinates(newCoordinates.a, newCoordinates.b);
+
+  this._game._removeRobot(oldCoordinates.a, oldCoordinates.b);
+  this._game._setRobot(newCoordinates.a, newCoordinates.b, this);
+
+  this._game.emit('move', this, oldCoordinates);
+};
+
 Robot.prototype.build = function() {
   this._game.buildRobot(this);
 };
@@ -72,24 +91,63 @@ Robot.prototype.scan = function() {
   //if (
 };
 
-Robot.prototype.nextStep = function() {
-  var operation = this._operation || 'ready';
-  this._invoke(operation);
+Robot._getCallbackName = function(instruction) {
+  var firstLetter = instruction.substr(0, 1);
+  var remainingLetters = instruction.substr(1);
 
+  return 'after' + firstLetter.toUpperCase() + remainingLetters;
 };
 
-Robot.prototype._invoke = function(operation) {
-  var name = operation.substr(0, 1).toUpperCase() + operation.substr(1);
-  var r = this._code.main['after' + name].apply({}, this._args);
-  this._args = [];
+Robot.prototype.nextTick = function() {
+  if (this._remainingCycles > 0) {
+    this._remainingCycles--;
+    return;
+  }
+
+  var executeFn = instructions[this._currentInstruction].execute;
+  var resultArgs = executeFn.call({}, this._game, this, this._currentArgs);
+  if (resultArgs) {
+    resultArgs = [].concat(resultArgs);
+  }
+
+  var callbackName = Robot._getCallbackName(this._currentInstruction);
+  var callbackFn = this._code[this._currentProgram][callbackName];
+
+  if (!callbackFn) {
+    console.log('missing callback: ' + callbackName);
+    this._commitSuicide();
+    return;
+  }
+
+  var nextArgs = callbackFn.apply({}, resultArgs || []);
+  if (!nextArgs) {
+    console.log('emtpy method: ' + callbackName);
+    this._commitSuicide();
+    return;
+  }
+  var nextInstruction = nextArgs.shift();
+
+  if (!(nextInstruction in instructions)) {
+    console.log('unknown instruction: ' + nextInstruction);
+    this._commitSuicide();
+    return;
+  }
+
+  var costs = instructions[nextInstruction].costs;
+  if (typeof costs === 'function') {
+    costs = costs.call({}, this._game, this);
+  }
 
-  if (!r) {
+  if (costs instanceof Error) {
+    console.log('costs error: ' + costs.message);
     this._commitSuicide();
     return;
   }
 
-  this._operation = r.shift();
-  this[this._operation].apply(this, r);
+  this._remainingCycles = costs;
+  this._currentInstruction = nextInstruction;
+  this._currentArgs = nextArgs;
+  //console.log(this._currentInstruction, this._currentArgs);
 };
 
 Robot.prototype._commitSuicide = function() {
diff --git a/js/lib/visualizer.js b/js/lib/visualizer.js
index 2e5fa0c..65c7211 100644
--- a/js/lib/visualizer.js
+++ b/js/lib/visualizer.js
@@ -17,6 +17,7 @@ Visualizer.prototype.render = function(game) {
   this._renderGrid();
 
   game.on('rotate', this._handleRotate.bind(this));
+  game.on('move', this._handleMove.bind(this));
   game.on('spawn', this._handleSpawn.bind(this));
   game.on('death', this._handleDeath.bind(this));
 };
@@ -69,6 +70,17 @@ Visualizer.prototype._handleRotate = function(robot) {
     .addClass('rotate_' + rotation);
 };
 
+Visualizer.prototype._handleMove = function(robot, oldCoordinates) {
+  var newCoordinates = robot.getCoordinates();
+
+  var $oldTd = this._getTd(oldCoordinates);
+  var $newTd = this._getTd(newCoordinates);
+
+  $newTd.append($oldTd.children().remove());
+  $newTd.attr('class', $oldTd.attr('class'));
+  $oldTd.attr('class', '');
+};
+
 Visualizer.prototype._handleSpawn = function(robot) {
   var coordinates = robot.getCoordinates();
   var $td = this._getTd(coordinates);
diff --git a/js/main.js b/js/main.js
index c131c39..58057fb 100644
--- a/js/main.js
+++ b/js/main.js
@@ -1,10 +1,25 @@
 $(function() {
   var TIMEOUT = 0;
 
+  var programs = {};
+  Program.load('js/program/flooder.js', function(program) {
+    programs.red = program;
+    onProgramLoad();
+  });
   Program.load('js/program/spinner.js', function(program) {
-    var game = Game.create(32);
-    game.add('red', program);
-    game.add('blue', program);
+    programs.blue = program;
+    onProgramLoad();
+  });
+
+
+  function onProgramLoad() {
+    if (Object.keys(programs).length < 2) {
+      return;
+    }
+
+    var game = Game.create(20);
+    game.add('red', programs.red);
+    game.add('blue', programs.blue);
 
     var visualizer = Visualizer.create($('.js_container'));
     visualizer.render(game);
@@ -12,7 +27,7 @@ $(function() {
     var interval;
     function continueGame() {
       interval = setInterval(function() {
-        game.nextStep();
+        game.nextTick();
       }, TIMEOUT);
     }
 
@@ -32,23 +47,5 @@ $(function() {
     });
 
     continueGame();
-  });
-
-  //var grid = Grid.create(8);
-  //var visualizer = Visualizer.create();
-
-  //var SIZE = 8;
-  //var html = ['<table>'];
-
-  //for (var a = 0; a < SIZE; a++) {
-    //html.push('<tr>');
-    //for (var b = 0; b < SIZE; b++) {
-      //html.push('<td>' + a + ', ' + b + '</td>');
-    //}
-    //html.push('</tr>');
-  //}
-
-  //html.push('</table>');
-
-  //$('.js_grid_container').html(html.join('\n'));
+  };
 });
diff --git a/js/program/flooder.js b/js/program/flooder.js
index a5e676b..b0eb9ff 100644
--- a/js/program/flooder.js
+++ b/js/program/flooder.js
@@ -1,5 +1,5 @@
 main: {
-  afterReady: function() {
+  afterInit: function() {
     return ['scan'];
   },
   afterScan: function(result) {
@@ -13,16 +13,29 @@ main: {
 
     return ['rotate', 'right'];
   },
-  afterBuild: function() {
-    return ['transfer', 'main'];
-  },
   afterTransfer: function() {
     return ['rotate', 'right'];
   },
+  afterBuild: function() {
+    return ['rotate', 'right'];
+  },
   afterRotate: function() {
     return ['scan'];
   }
 },
 virus: {
-  afterReady: function() {}
+  afterInit: function() {
+    return ['scan'];
+  },
+  afterScan: function(result) {
+    if (result === 'empty') {
+      return;
+    }
+
+    if (result === 'friend') {
+      return ['transfer', 'main'];
+    }
+
+    return;
+  },
 }
diff --git a/js/program/spinner.js b/js/program/spinner.js
index 6908553..349a609 100644
--- a/js/program/spinner.js
+++ b/js/program/spinner.js
@@ -1,11 +1,11 @@
 main: {
-  afterReady: function() {
+  afterInit: function() {
     return ['build'];
   },
   afterBuild: function() {
-    return ['rotate', 'right'];
+    return ['rotate', 'left'];
   },
   afterRotate: function() {
     return ['build'];
-  }
+  },
 }