OpenBlocks - Magnetic OpenLOCK Grid

[Dungeon Blocks](https://www.myminifactory.com/users/DungeonBlocks#/) compatible grid system that adds some additional options:
- All sizes from 1x1 up to 6x6
- OpenLOCK sockets to connect grid parts with the widely used [OpenLOCK](https://www.printablescenery.com/product/open-lock/) clip
- Magnetic spheres (5mm) that quickly stick together grid parts - similar to Devon Jones' [OpenForge bases](https://www.thingiverse.com/thing:1910974)

Instructions for adding magnet spheres:
- Start with the common 3x3 grid part
- Print 8 pieces of the grid plug
- Adding the magnets:
- put one magnet into one of the round bottom holes
- pull it to the edge of the grid part by means of some metallic tool
- stuff one plug into the hole (the plug dimensions should make the plug stay in place without glue but your mileage may vary)

Print Settings:
- nozzle: 0.4 mm
- layers: 0.20 mm
- bottom solid layers: 4
- top solid layers: 5
- infill: 15%
- no supports