diff --git a/pattern_generator/lib/pattern_generator.rb b/pattern_generator/lib/pattern_generator.rb
new file mode 100644
index 0000000..5024bc4
--- /dev/null
+++ b/pattern_generator/lib/pattern_generator.rb
@@ -0,0 +1,59 @@
+class PatternGenerator
+
+  def initialize(pattern)
+    @pattern = pattern.chars
+    @letters = ["A", "B", "C", "D", "E", "F", "G",
+                "H", "J", "K", "L", "M", "N", "P",
+                "Q", "R", "S", "T", "U", "V", "W",
+                "X", "Y", "Z"]
+    @serials = {}
+    @total = (10**pattern.count("N"))*(26**pattern.count("X"))
+    @count = 0
+  end
+
+
+  def find_serial
+    serial = @pattern.reduce("") do |result, char_type|
+      result += random_capital_letter if char_type == "X"
+      result += random_number.to_s    if char_type == "N"
+      result
+    end
+  end
+
+  def random_capital_letter
+    @letters[random_selector]
+  end
+
+  def random_number
+    Random.rand(2..9)
+  end
+
+  def random_selector
+    Random.rand(0..23)
+  end
+
+  def all_serials
+    until @count != @total
+      new_serial = find_serial
+      if !@serials.has_key?(new_serial)
+        @serials[new_serial] = 1
+        @count += 1
+      end
+    end
+    @serials
+  end
+
+  # def all_serials
+  #   # first char  all positions 0 - 23 rest 2
+  #   # second char all positions 1 - 23 rest A/2
+  #   # third char all numbers 3-9 rest A/2
+  #   # fourth char all positions 1 - 23 rest A/2
+  #   # fifth char all numbers 3-9 rest A/2
+  #   all_for_first_char
+  # end
+  #
+  # def all_for_first_char
+  #
+  # end
+
+end
diff --git a/pattern_generator/test/pattern_generator_test.rb b/pattern_generator/test/pattern_generator_test.rb
new file mode 100644
index 0000000..074be7a
--- /dev/null
+++ b/pattern_generator/test/pattern_generator_test.rb
@@ -0,0 +1,100 @@
+require 'minitest/autorun'
+require 'minitest/pride'
+require 'pry'
+require './lib/pattern_generator'
+
+class PatternGeneratorTest < Minitest::Test
+
+  def set_up
+    @letters = {"A"=> true, "B"=> true, "C"=> true, "D"=> true,
+              "E"=> true, "F"=> true, "G"=> true, "H"=> true,
+              "J"=> true, "K"=> true, "L"=> true, "M"=> true,
+              "N"=> true, "P"=> true, "Q"=> true, "R"=> true,
+              "S"=> true, "T"=> true, "U"=> true, "V"=> true,
+              "W"=> true, "X" => true, "Y"=> true, "Z"=> true
+               }
+    @numbers = {"2" => true, "3" => true, "4" => true, "5" => true,
+                "6" => true, "7" => true, "8" => true, "9" => true,
+                }
+  end
+
+  def test_it_can_generate_a_pattern
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern = pattern_generator.find_serial
+
+    assert_equal 5, pattern.length
+  end
+
+  def test_the_first_char_is_a_captial_letter
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern = pattern_generator.find_serial
+
+    assert @letters[pattern[0]]
+  end
+
+  def test_the_second_char_is_a_capital_letter
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern = pattern_generator.find_serial
+
+    assert @letters[pattern[1]]
+  end
+
+  def test_the_third_char_is_a_number
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern = pattern_generator.find_serial
+
+    assert @numbers[pattern[2]]
+  end
+
+  def test_the_fourth_char_is_a_capital_letter
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern = pattern_generator.find_serial
+
+    assert @letters[pattern[3]]
+  end
+
+  def test_the_fifth_char_is_a_number
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern = pattern_generator.find_serial
+
+    assert @numbers[pattern[4]]
+  end
+
+  def test_two_patterns_are_not_the_same
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern_1 = pattern_generator.find_serial
+    pattern_2 = pattern_generator.find_serial
+
+    refute pattern_1 == pattern_2
+  end
+
+  def test_it_can_generate_for_different_patterns
+    set_up
+    pattern_generator = PatternGenerator.new("XXNXN")
+    pattern_1 = pattern_generator.find_serial
+
+    pattern_generator = PatternGenerator.new("XXNXNXX")
+    pattern_2 = pattern_generator.find_serial
+
+    assert pattern_1
+    assert pattern_2
+  end
+
+  def test_it_returns_a_hash_of_serials
+    set_up
+    pattern_generator = PatternGenerator.new("XXN")
+    serials = pattern_generator.all_serials
+    puts serials
+    assert serials.keys == serials.keys.uniq
+  end
+
+
+
+
+end