Grey balls are released one by one to roll down along a railway that consists of several sections connected together in zigzag shape.
Each section has a gate (hole) and its cover. The video shows only one section.
If the cover is open, the balls fall through the gate.
The contestant tries to hit violet round target for closing the gate to let the ball continue rolling in the railway to the final basket at the railway lower end. Winner is who gets most balls in the basket.from 34th minute.
This video is made on request of a YouTuber, wjf213, who wants a mechanism purely mechanical.
When the red bullet hits violet target, a plate fixed to the target pushes green arm (fixed to the blue gate cover) to close the gate.
After passing the cover, the ball pushes the blue arm (fixed to the blue gate cover) to open the gate.
Red spring, creating snap action, keeps the cover firmly at its closing or opening positions.
At those positions axis of the revolute joint of the cover is not in the plane containing axes of the spring pins.
Two orange pins (one long, one short) are stoppers for the cover.
Green spring is for reducing oscillation of the target.