A simple ball-maze doesn't meet the requirement of a real puzzle as the eye can simply follow the path and the actual challenge is the plain motoric difficulty. Not so this concept of a double sided maze. The ball has to change the sides two times.

My build was done on a desktop cnc-machine by Stepcraft from 2 sheets of 6 mm beech plywood using a spiral-toothed 3 mm flute and a 2 mm end mill for plastics to cut the acrylic glass to cover the maze. It took quite some time to clean out the channels with sand paper.

I used a 3 mm steel ball from bike wheel hub.

Visit https://www.zenziwerken.de/en/ for more designs.