[x,y,z]=meshgrid(-6:.15:6, -6:.15:6, -6:.15:6);
k=5;
a=0.95;
b=0.8;
f=(x.^2+y.^2+z.^2-a*k.^2).^2-b*((z-k).^2-2*x.^2).*((z+k).^2-2*y.^2);
const=0;
surfcv(x,y,z,f,const)
shading interp
axis off
colormap(spring)
light
lighting phong
set(gcf,'color',[0.3761 0 1.0000])