Duplo cannon

[Magnus Forsberg]

Are ~parts of the same assembly allowed to collide, i.e. have surfaces that pass thru each other?

E.g. can the mounting of a screw be a flat surface just under the head? This would mean that the threaded part (cylinder) would pass right thru the flat surface.

Since we don't know the correct length, or the depth, I would say yes.
Maybe add an edge prim to indicate there's a hole?