sub getPos{
	($x,$y,$s)=@_;($d=$x+$y)*($d++)/2
	+($d%2?$y:$x)-($d>$s)*($d-$s)**2
}
##</code><code>##

for(my $x = 0; $x < $size; $x++){
	for(my $y = 0; $y < $size; $y++){
		print getPos($x, $y, $size)."  ";
	}
	print "\n";
}

##</code><code>##

0  1  5  6  14  15  27  28  44  45  
2  4  7  13  16  26  29  43  46  63  
3  8  12  17  25  30  42  47  62  64  
9  11  18  24  31  41  48  61  65  78  
10  19  23  32  40  49  60  66  77  79  
20  22  33  39  50  59  67  76  80  89  
21  34  38  51  58  68  75  81  88  90  
35  37  52  57  69  74  82  87  91  96  
36  53  56  70  73  83  86  92  95  97  
54  55  71  72  84  85  93  94  98  99

##</code><code>##

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;
	}
}

##</code><code>##

$==pop;print map{$y=$_;map(($d=$y+$_)*$d++/2-($d>$=)*($d-$=)**2+($d&1?$_:$y).$",@m),$/}@m=0..$=-1