match diagonal text

[arivu198314]

I need to match particular number in the matrix formatted text like

$a='
220021
000200
020222
020222';

From the above matrix i need to find diagonal 1111 or 2222.

I have written the code, but its very big. So can anyone optimize this code

my $arraycount=0; my @charArray=(); my @linear=grep length, split /\n/
+, $a;
        @lines=@linear;
    while (length join "", @linear)
    {
        $reversed=join("", map { s/(.)//s ? $1 : "" } @linear);
        push (@charArray, [split //, $reversed]);
    }
    
    my $result; my $findString='1|2';
    for(my $rw=0; $rw < (@lines-3); $rw++)
    {
        my @line=split //, $lines[$rw];
        foreach my $index (grep {$line[$_]=~m/$findString/} 0..$#line)
        {
            if (($line[$index].$charArray[$index+1][$rw+1].$charArray[
+$index+2][$rw+2].$charArray[$index+3][$rw+3] eq $line[$index] x 4) or
+ ($line[$index].$charArray[$index-1][$rw+1].$charArray[$index-2][$rw+
+2].$charArray[$index-3][$rw+3] eq $line[$index] x 4))
            {
                print $line[$index];
            }
        }
    }