Impossible Spiral Passthrough with Captive Ball

This Impossible Spiral Passthrough with Ball is a mesmerizing mechanical puzzle that looks like it shouldn’t work — but it does!The design features a twisting spiral tower that traps a ball inside a helical cage. The ball appears impossible to insert or remove, creating the illusion that it’s magically locked inside the structure. The spiral geometry allows the ball to travel through the center while staying captured within the twisting outer shell.This model prints fully assembled and works right off the build plate — no supports, but may print better with a brim with the ball, no extra parts, and no assembly required.Perfect for:Desk toysFidgeting and focusMechanical puzzle collectorsDemonstrating cool 3D printing geometryThe smooth twisting motion and the satisfying movement of the captive ball make it a great conversation starter. • Print-in-place mechanism• Captive moving ball inside spiral cage• No supports required• No assembly required• Smooth passthrough motion• Great desk fid