double R = 4;
double r = 1;
rot_x=0.0;
rot_y=0.0;
rot_z=1.0;
int i =0;
surface_green=50;
color_file_format=jpg;
loop:
	surface=2*R^2*(z^2-x^2-y^2)+(R^2-r^2)^2-2*r^2*(x^2+y^2+z^2)+(x^2+y^2+z^2)^2;
	draw_surface;
	//rot_x=rot_x+0.05;
	rot_y=rot_y+0.05;
	filename="torus"+itostrn(3,i)+".jpg";
	//save_color_image;
	i=i+1;
	clear_screen;
if( i < 50 ) goto loop;