$ ruby -ryaml -rpp -e 'x = YAML.load_file("cyclic_test2.yml"); print PP.pp(x);'
{"key0"=>{"zero"=>0},
 "key1"=>{"zero"=>0, "subkey_a"=>"asdf", "subkey_b"=>"qwer", "Z"=>"key1.Z"},
 "key2"=>
  {"everyday"=>"apple",
   "X"=>1,
   "Y"=>2,
   "Z"=>"key2.Z",
   "A"=>
    [{"zero"=>"00"},
     {"zero"=>0, "subkey_a"=>"asdf", "subkey_b"=>"qwer", "Z"=>"key1.Z"},
     {"everyday"=>"shuffling", "X"=>1, "Y"=>3000, "Z"=>"key2.Z"}],
   "zero"=>0},
 "key3"=>
  {"zero"=>0,
   "subkey_a"=>"foo",
   "subkey_b"=>"qwer",
   "Z"=>"key1.Z",
   "everyday"=>"apple",
   "X"=>1,
   "Y"=>2,
   "A"=>
    [{"zero"=>"00"},
     {"zero"=>0, "subkey_a"=>"asdf", "subkey_b"=>"qwer", "Z"=>"key1.Z"},
     {"everyday"=>"shuffling", "X"=>1, "Y"=>3000, "Z"=>"key2.Z"}],
   "subkey_c"=>"bar",
   "deeper"=>{"challenger"=>"deep", "zero"=>0}}}