/* decartes curve */
delta:-1/4;
poly:x^3+y^3-3*x*y -delta;
surfplot(poly);

/* lemniscate(1)*/
poly:(x^2*(9-x^2)-4*y^2);
surfplot(poly);
/* lemniscate(1)*/
poly:(x^2*(9-x^2)-4*y^2)*x*y;
surfplot(poly);

/* Ducky */
poly:(x^2+y^2-9)*((x-2)^2+(y-1)^2-1)*((x+2)^2+(y-1)^2-1)*(x^2/9+2*(y+1)^2-1);
surfplot(poly);

put(surf,0.6,rot_x);
put(surf,0.6,rot_y);
put(surf,0.6,rot_x);
put(surf,0.6,rot_z);
put(surf,0.06,scale_x);
put(surf,0.06,scale_y);
put(surf,0.06,scale_z);
poly:x^2*y^2+x^2*z^2+y^2*z^2-x*y*z;
surfplot(poly);
system("echo \"transparence=50;illumination=ambient_light+diffuse_light+reflected_light+transmitted_light;\" >surf.tmpx");
system("cat surf.tmp>>surf.tmpx");
system("mv surf.tmpx surf.tmp");
system("echo \"plane=x+y+z-0.05;\">>surf.tmp");
system("echo \"curve_red=255;\">>surf.tmp");
system("echo \"curve_green=0;\">>surf.tmp");
system("echo \"curve_blue=0;\">>surf.tmp");
system("echo \"cut_with_plane;\">>surf.tmp");
system("echo \"plane=x+y+z+0.05;\">>surf.tmp");
system("echo \"curve_red=0;\">>surf.tmp");
system("echo \"curve_green=255;\">>surf.tmp");
system("echo \"curve_blue=0;\">>surf.tmp");
system("echo \"cut_with_plane;\">>surf.tmp");
system("surf -x surf.tmp>surf.log&");

/* Barth Diec */
/* set rot_x,y,z and scale_x,y,z */
put(surf,0.6,rot_x);
put(surf,0.2,rot_y);
put(surf,0.6,rot_z);
put(surf,0.3,scale_x);
put(surf,0.3,scale_y);
put(surf,0.3,scale_z);
/* set tau */
tau:(1+sqrt(5))/2;
/* polynomial */
poly:8*(x^2-tau^4*y^2)*(y^2-tau^4*z^2)*(z^2-tau^4*x^2)*
(x^4+y^4+z^4-2*(x^2*y^2+y^2*z^2+z^2*x^2))+
(3+5*tau)*(x^2+y^2+z^2-1)^2*(x^2+y^2+z^2-(2-tau))^2;
surfplot(poly);

/* Barth Diec */
/* set rot_x,y,z and scale_x,y,z */
put(surf,0.6,rot_x);
put(surf,0.2,rot_y);
put(surf,0.6,rot_z);
put(surf,0.3,scale_x);
put(surf,0.3,scale_y);
put(surf,0.3,scale_z);
/* set tau */
tau:float((1+sqrt(5))/2);
/* polynomial */
poly:8*(x^2-tau^4*y^2)*(y^2-tau^4*z^2)*(z^2-tau^4*x^2)*
(x^4+y^4+z^4-2*(x^2*y^2+y^2*z^2+z^2*x^2))+
(3+5*tau)*(x^2+y^2+z^2-1)^2*(x^2+y^2+z^2-(2-tau))^2;
surfplot(poly);