% perl -MList::MoreUtils=uniq -nwle 'END{ warn +(times)[0],"\n" }
  print $_ if /^(?^:(.)(?!\1)(.)(?!\1|\2)(.)\3\2\3\3\2(?!\1|\2|\3)(.)\4\2)$/
' /usr/share/dict/hv.words | wc -l
0.08
2
% perl -MList::MoreUtils=uniq -nwle 'END{ warn +(times)[0],"\n" }
  print $_ if /^(?:(.)(.)(.)\3\2\3\3\2(.)\4\2$(?(?{ 4 != uniq $1, $2, $3, $4 })(?!)))/
' /usr/share/dict/hv.words | wc -l
0.09
2
%