First update:
What do you mean by this?
It’s possible, but it would probably render an unexpected result. You won’t see the interior of the object, as there are no 3D object. This rendering is based on a trick, and this trick requires the top face to be drawn!
A color painted on the bottom of the “holes”. Or call it background:
My idea was to use it on photos like this, and then I don’t need the top color. But it can be removed very easily in GIMP itself.
One more, can you increase the max number for depth to 100?
Nice cookie cutter you have there, David.