// the Neovius surface: https://en.wikipedia.org/wiki/Neovius_surface

let
    neovius = make_shape {
        dist[x,y,z,_] = -(3*(cos x+cos y+cos z) + 4*cos x*cos y*cos z);
        is_3d = true;
    };

in
neovius >> shell .2 >> lipschitz 10 `intersection` cube 20