camera{location<1,0,7>look_at 0}light_source{<-9,0,9>rgb<1,0,0>}light_source{9*z rgb<0,1,0>}light_source{<9,0,9>rgb<0,0,1>}isosurface{function{cos(2*x)+cos(2*y)+cos(2*z)}contained_by{sphere{0,5}}open pigment{rgb 1} finish{phong 1}}