spiral_numbers(5);
sub spiral_numbers
{
	my $n = shift;
	local $_;

	my @nums = 1 .. $n**2;

	my @a = ( [ pop @nums ] );

	for my $k ( 2 .. $n )
	{
		if ( $k & 1 ) # odd
		{
			push @$_, pop @nums
				for @a[ reverse 0 .. $k-2 ];
			unshift @a, my $r=[];
			unshift @$r, pop @nums
				for 1 .. $k;
		}
		else # even
		{
			unshift @$_, pop @nums
				for @a[ 0 .. $k-2 ];
			push @a, my $r=[];
			push @$r, pop @nums
				for 1 .. $k;
		}
	}

	# print it out

	local( $\, $, ) = ( "\n", "\t" );

	if ( $n & 1 ) # odd
	{
		print @$_ for @a;
	}
	else # even
	{
		print reverse @$_ for reverse @a;
	}
}