move(z) = { my (w=max(abs(real(z)), abs(imag(z)))); if (imag(z)==-w, z+1, imag(z)==+w, z-1, real(z)==-w, z-I, z+I ); } z=0; for (n=0, 10000, print (n " " imag(z)); z=move(z)) quit