test.rb

#!/usr/bin/env ruby

class FooBar
    include Enumerable
    def initialize( array1 , array2 )
        @array_out = Array.new
        if array1 != [] and array2 != []
            for i in array1
                for j in array2
                    k = [i,j].join("|") 
                    @array_out.push( k )
                end
            end 
        end
    end
    def each
        current_index = 0
        while current_index < @array_out.size
            yield @array_out[current_index]
            current_index += 1
        end
    end
end

class Array 
    def reverse_iterate
        current_index = self.size-1
        while current_index >= 0
            yield self[current_index]
            current_index -= 1
        end
    end
end

#[2,4,5,6,9].reverse_iterate { |i| puts i.inspect }

x = FooBar.new( (1..3) , [4,6] )
x.each{ |i| puts i.inspect }

y = FooBar.new( [ 'A' , 'B' , 'a' , 'b' ] , [4,6] )
y.each{ |i| puts i.inspect }