This is what occurred to me:

@pics = (1..100);
for($x=0;$x<@pics;$x++){
  print "displaying pic number $pics[$x] \n";
  if (($x+1) % 5 == 0){ # because zero mod 5 is zero too
    print "...and starting a new row.\n";
  }
}
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--

($_='jjjuuusssttt annootthheer
     pppeeerrrlll haaaccckkeer')=~y/a-z//s;print;
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