for my $y ( 1 .. 3 ) { 
    for my $x ( 1 .. 3 ) { 
        print "[$x:$y] => ", $x*$y-1; 
    } 
}
[1:1] =>  0
[2:1] =>  1
[3:1] =>  2
[1:2] =>  1
[2:2] =>  3
[3:2] =>  5
[1:3] =>  2
[2:3] =>  5
[3:3] =>  8