I love Snarkwise's Zencubes, however because of the amount of metal on the UP! printer - it caused the majority of the magnets to jump out, no matter what I did to prevent it. So this is the fix! A mash-up to make the Zencube take Zenpins! A BIG thankyou to Snarkwise for posting the scad files which really helped my learning curve of openscad in this process! I'll upload the scad file once I've cleaned up my code. These also have a flat bottom (no cross for removing a pin). Please note - as much as I have tested these and the pins stay put quite well - if these are going to be for toys - adult supervision and only for kids old enough to know NOT to put things in their mouths! This design includes small parts that could be harmful. I have included two different clearances - and the test-blocks to save time. These are so you can find the most snug fit of the pins. On the UP! I prefer the 0.2mm clearance. The easiest way to get the pins in - once magnet is in the pin, put the pin on the diagonal with the opening for the magnet lightly wedged into the edge of the hole (see pics) and then push the other side in. With 0.2mm clearance and this technique, the pins are a really snug fit and the only way to get them back out is with a flat-head jewellers screwdriver.