/\abcd
a*bc*(ab)+
 /\/\/ bacbbcdaccabbcaddabc
 /\/\/ aadbcbadbbbbdbaaacaa
 /\/\/ cadcacccbdabccbdcbcd
 \     abaadbdbabbabdcaadba
 /\/\/ dbdbacaccdccabccbacd
 /\/\/ adcacbaccccbbbdbbbdb
 /\/\/ bbdacaccbdccddabacdc
  \    ddcbaabdcbabdabddbdc
 /\/\/ cbacbcbaaddbcaaabccd
 /\/\/ adbcdbacbbaccbcadbdd
 /\/\/ cbaaaaccadcbdadcbaac
 /\/\/ bcdbdbdacaccacaacddd
 /\/\/ acdabdcbacbbbccdbcda
 /\/\/ abbcbcaacbbccbdcbcbc
 /\/\/ ccabadbccccbacdbaddb
 /\/\/ baabadbcbcbdcaccaaaa
   \   bdacaababdbbcaccadaa
    \  ccababdbabbacbcbdddd
     \ ddcaaaabdbcddbabaddd
      \bdbadbaacdbbcbbbbabd
 /\/\/ acbbccbbdacbddabdcad
      /ccaddccbbbacbdadbaba
     / cbcdababbdbdbaacbcda
 /\/\/ cddcbacdaacbbbdddbbc
 /\/\/ bcbaabcccaddaaabbacd
 /\/\/ ddbacdccccdadbdcacdc
 /\/\/ bcdbdcaaacdaddabccbd
    /  bddcdbabbacdbacdddab
 /\/\/ bbaaabbcaacdbbccddaa
 /\/\/ cadddddbdabaddaaacdc
 /\/\/ ccccbdddcdacdbaabcac
 /\/\/ acdbcdadabdbbcbcdacb
 /\/\/ cadabacbbdcabcdadcca
 /\/\/ ddbcbadddacaaaacbada
   /   babddaaabbbacdccbaac
  /    dabaaccabababcdcbbad
 /\/\/ cdbcbbbcadcddaccdbca
 /\/\/ aaadcacdcabaabaadbcb
 /     bcabbddbbbcbacacaddc
 /\/\/ dbadaddcaaaaaaadaaba