foreach my $w (3..100) {
    foreach my $x (2..$w-1) {
        foreach my $y (1..$x-1) {
            foreach my $z (0..$y-1) {
                next if ($z-$y==$y-$x and $y-$x==$x-$w);
                
                ...;
            }
        }
    }
}