c:\@Work\Perl>perl -wMstrict -le
"my $string = 'IIIIMMMMMMMOOOOOOOOOOMMMMMMMMMMMMMMMIIIIIIMMMMOOOO';
 ;;
 while ($string =~ /M+/g) {
   my ($start, $end) = ($-[0], $+[0]);
   print qq{start $start, end $end};
   }
"
start 4, end 11
start 21, end 36
start 42, end 46