Insane marble puzzle thang! Here is a demonstration of SUPERPLEXUS CIRCLES, a 24″ diameter commission by artist/thinker/puzzle-maker/genius Michael McGinnis. Playtime is about an hour for a player from start to finish, and has the player needing to flip their play axis to reach the various marble stages. ‘Circles’ is meant to be challenging, though doable. It’s made from birch plywood, acrylic, Jatoba, and stainless steel – there’s more info and interesting creations at Michael’s site – https://www.superplexus.com/.
It really gets the cogs turning. Would love to see the challenge in person, and/or collaborate with Michael in future.