sub getPos{
	my ($x,$y,$size)=@_;
	my $d = $x+$y;
	my $m = $d-$size;
	my $p = (($d%2)?$x:$y);
	my $dist = ($d*($d+1))/2;
	my $index = $dist + $p;
	if($d >= $size){
		$index -= ($m+1)**2;
	}
}