Improved Dungeon Parts

*UPDATED NOTE: These parts were designed back when hobby 3D printers were in their infancy. Tolerances were not great so snap-together designs weren't reliable. That is the reason for the loops and magnet design. Today, with the great advances in 3D printer technology, we can print much better and more accurate designs. For example, I've started releasing a new set of 3D Printable Modular Dungeons. https://www.thingiverse.com/thing:3333475
Instead of re-inventing the wheel, I've designed the pa