diff --git a/hamming.rb b/hamming.rb
new file mode 100644
index 0000000..4ab3166
--- /dev/null
+++ b/hamming.rb
@@ -0,0 +1,44 @@
+#class Hamming
+#   def self.compute(dna,sdna)
+#     c = []
+#     d = dna.split('')
+#     s = sdna.split('')
+#     if s.length != d.length
+#        raise ArgumentError.new("First or second strand to long") #could have used unless
+#     end
+#     not_matching_element = d.dup
+#     f = 0
+#     until f == s.length
+#       s.each_index do |i|
+#         if not_matching_element[i] != s[i]
+#           c << s[i]
+#
+#         end
+#       f += 1
+#       end
+#     end
+#     return c.length
+#   end
+# end
+#
+#
+#
+
+
+class Hamming
+  def self.compute(dna,sdna, counter = 0)
+    if dna.length != sdna.length
+      raise ArgumentError
+    end
+
+    if dna.length == 0 && sdna.length == 0
+      return counter
+
+    elsif
+      dna[0] != sdna[0]
+      counter += 1
+    end
+    return self.compute(dna[1..-1], sdna[1..-1], counter)
+
+  end
+end
diff --git a/hamming_test.rb b/hamming_test.rb
index 2d1f9d7..1ab7602 100644
--- a/hamming_test.rb
+++ b/hamming_test.rb
@@ -4,72 +4,70 @@
 
 class HammingTest < Minitest::Test
   def test_identical_strands
-    skip
+
     assert_equal 0, Hamming.compute('A', 'A')
   end
 
   def test_long_identical_strands
-    skip
     assert_equal 0, Hamming.compute('GGACTGA', 'GGACTGA')
   end
 
   def test_complete_distance_in_single_nucleotide_strands
-    skip
     assert_equal 1, Hamming.compute('A', 'G')
   end
 
   def test_complete_distance_in_small_strands
-    skip
+
     assert_equal 2, Hamming.compute('AG', 'CT')
   end
 
   def test_small_distance_in_small_strands
-    skip
+
     assert_equal 1, Hamming.compute('AT', 'CT')
   end
 
   def test_small_distance
-    skip
+
     assert_equal 1, Hamming.compute('GGACG', 'GGTCG')
   end
 
   def test_small_distance_in_long_strands
-    skip
+
     assert_equal 2, Hamming.compute('ACCAGGG', 'ACTATGG')
   end
 
   def test_non_unique_character_in_first_strand
-    skip
+
     assert_equal 1, Hamming.compute('AGA', 'AGG')
   end
 
   def test_non_unique_character_in_second_strand
-    skip
+
     assert_equal 1, Hamming.compute('AGG', 'AGA')
   end
 
   def test_large_distance
-    skip
+  
     assert_equal 4, Hamming.compute('GATACA', 'GCATAA')
   end
 
   def test_large_distance_in_off_by_one_strand
-    skip
+
     assert_equal 9, Hamming.compute('GGACGGATTCTG', 'AGGACGGATTCT')
   end
 
   def test_empty_strands
-    skip
+
     assert_equal 0, Hamming.compute('', '')
   end
 
   def test_disallow_first_strand_longer
-    skip
+
     assert_raises(ArgumentError) { Hamming.compute('AATG', 'AAA') }
   end
 
   def test_disallow_second_strand_longer
-    skip
+
     assert_raises(ArgumentError) { Hamming.compute('ATA', 'AGTG') }
   end
 end