Your initial solution was SO much better than mine. So that's the one I'm using.

I needed to find the first random non-blank element. Using shuffle worked, but I was looking for a neater and simpler way.

Again, thank you.

My final -

        while (1) {
            my $xda = int rand $total + 1;
            if ( defined $aob[$xda][ $y - 1 ] ) {
                $aob[$x][$y] = $z + $aob[$xda][ $y - 1 ];
                last;
            }
        }
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. Using 'defined' is actually better in this case than using "" or q{}. No warnings.