local $_= "Stop tip stoop put up, tops steep 'creap' sleep soap!";
my @words;
push @words, $1
#   while  /(\b\w*(?!(.)\2)\w[aeiou]p\b)/g;
    while  /(\b(?:\w*(?!(.)\2)\w)?[aeiou]p\b)/g;
print "( @words )\n";
__END__
( Stop tip up creap soap )