allocate mem(2^30)

G = matrix(2*W=1000, 2*W)
flip(z) = my (x=real(z)+W, y=imag(z)+W); G[x,y]=1-G[x,y]

{
	z = 0;
	d = I;
	black = 0;
	for (n=0, 500,
		print (n " " black);
		f = flip(z);
		black -= (-1)^f;

		if (real(z)%2==0,
			\\ octogonal cell
			if (f,
				d *= 1+I,
				d *= 1-I,
			),

			\\ square cell
			if (f,
				d *= I,
				d *= -I
			);
		);

		d /= gcd(real(d),imag(d));

		if (real(z)%2==0,
			\\ octogonal cell
			if (abs(d)==1,
				z += 2*d,
				z += d
			),

			\\ square cell
			z += d
		);
	);
}

quit