foreach (<$lines>)
{
    chomp;
    for my $l (0..length()-1)
    {
        my ($digit) = /^.{$l}(.)/;
        if (defined $digit)
        {
            $row[$current][$l] = $1; 
        }
    }
    $current += 1;
}
[download]

A more Perl way to write that would be:

while ( <$lines> ) {
    chomp;
    push @row, [ split // ];
    }
[download]