c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @ra = (1, 1, 1, 2, 3, 4, 4, 4, 5, 6, 1, 1, 1);
 dd \@ra;
 ;;
 my $one;
 $one = pop @ra while $ra[-1] == 1;
 push @ra, $one if defined $one;
 dd \@ra;
"
[1, 1, 1 .. 4, 4, 4, 5, 6, 1, 1, 1]

[1, 1, 1 .. 4, 4, 4, 5, 6, 1]