This is a derivative of mattjoyce's marble run with pins(from filament) instead of magnets. Designed to attach to a non-magnetic surface...probably plywood.

Print. (I used 0.3 layer height and 3 perimeters) Drill holes appropriately spaced for the pins.(Angled would be less likely to come out put harder to get the correct angle.) Find someone that's kid enough to enjoy... Have fun!