This Phone Case Contains an Entire Recirculating Marble Machine

Strange Inventions Lab turned an iPhone 13 Pro case into a miniature marble machine. The case contains a track and an Archimedes-screw lift, so tilting the phone sends a ball through the course and raises it for another lap.

The creator describes it as an experimental design that needs a fairly specific angle and can occasionally jam. It uses 19 screws and 12 ball bearings to add a complete mechanical toy to an object normally designed to stay thin and unobtrusive.