light_source{1 1}#macro R()#declare T=function{internal(#end#macro G(B,C))}isosurface{function{-T(x,y,z,.1)}pigment{agate}translate}#undef T#end R()65G(-4,7)R()38G(-1,5)R()14G(1,8)R()22G(2,5)R()41G(4,11)plane{y,-1pigment{checker rgb 2rgb x}}