While this is not a fully featured sculpting app by any means, it’s meant to simulate the experience of carving a shape into some spinning material!
I and O: Sculpt surface inwards/outwards
P: Sculpt in or out depending on which side of the surface your cursor is on
Shift (either): Hold to rotate
Arrow keys up/down: Hold to increase/decrease spin speed
Arrow keys left/right: Cycle through a few different materials
E: Export to a .STL file on your desktop for 3D printing!
(may require additional processing on your end, since you can sculpt the shape down to zero thickness)