The pendulum starter is not an original Ravensburger GraviTrax part.

The idea is that you can load one ball ("marble") on top of the pendulum, and when a ball hits its bottom end, the ball on top will fall on the track. and that 9cm higher than the bottom track.

Its top end is an insert to the original GraviTrax part for the swirl or target hexagons.

You'll need a metal pin (part of a nail e.g.) about 2,5cm long and <2.8mm thick, to be tha axle of the pendulum.

My son and me invented this thing after having a lot of extra bridge piers, and then needed a way to got back up there.

Links to my other GraviTrax compatible parts: Tracks: https://www.thingiverse.com/thing:2738473 Curves, Straights, and Joins: https://www.thingiverse.com/thing:2738494 Magnetic cannon: https://www.thingiverse.com/thing:2738601 Bridge piers: https://www.thingiverse.com/thing:2738439