Wrote code so tests pass

lib/seq.rb

@@ -1,3 +1,74 @@
 class Seq
 
+  Infinity = 1.0/0
+
+  # Creates a new instance of Seq.
+  #
+  # @param list [Array] 
+  #   List of values to cycle over
+  # @param items [Integer] 
+  #   Number of values to return
+  # @param offset [Integer] 
+  #   Index of item in +list+ to start at
+  # @param default [Object]
+  #   Value to return when finished cycling
+  #
+  def initialize(list=[], items=Infinity, offset=0, default=nil)
+    @list    = list
+    @items   = items
+    @offset  = offset
+    @default = default
+
+    self.reset
+  end
+
+  def reset
+    @cycles = 0
+    @index  = @offset
+  end
+
+  def next
+    if ended?
+      @default
+    else
+      @list[@index].tap { inc }
+    end
+  end
+
+  def inc
+    @index  += 1
+    @cycles += 1
+    @index   = 0 if @index == @list.size
+  end
+
+  def each
+    until ended?
+      yield self.next
+    end
+  end
+
+  include Enumerable
+
+  def to_a(expanded=false)
+    if expanded
+      raise RangeError if infinite?
+
+      i, c = @index, @cycles
+      r = self.entries
+      @index, @cycles = i, c
+
+      r
+    else
+      @list
+    end
+  end
+
+  def infinite?
+    @items == Infinity
+  end
+
+  def ended?
+    @cycles >= @items
+  end
+
 end