Perl can help you a lot with your code if you let it. In your case, adding the line use strict; near the top of your program will make Perl tell you about undeclared variables.

In your case, you're declaring a variable @wire2 as an array, but you are actually using a hash %wire2 in the line:

    $wire2{ "a"} .= $x;
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This is why it's always recommended that you add the two lines near the top of your scripts:

use strict;
use warnings;
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