Update: these have fallen out of my favor. Note: not a good object if your magnets arent strong enough, annoying when stuff slides down, the clamp has to be the right size too. There are cylindrical holes for magnets and clamps too. Unfortunately due to extrusion difficulties i havent been able to test anything other than what is effectively the 'vanilla' thing without magnet hole or clamp. I have no need for any more, so wont be testing myself. Note: the idea of the clamp is that it is at the top of a whiteboard or something.(or at the bottom with a bit of the ziplock inside out) https://github.com/o-jasper/various_physibles contains the development versions.