Large Magnetic Box

This design born out of a very specific need of mine. I'm running a TTRPG game with a group of friends, and we take turns hosting the sessions. I was searching desperately for a box that is big (and especially deep) enough to keep all the bits and peaces I have to carry to the sessions, easily fit in a backpack and will not open while commuting (a bumpy ride by a bike) but non of the existing models clicked these three requirements at once. So I had to create my own model. The outer size of box is 23cmx23cmx8cm with a very little loss of usable space inside. When the lid is closed, there's no overhangs whatsoever, it becomes a perfect square prism. There are 4 indentations (2 each on opposing sides) where you can grip the lid and open it. Although the lid sits firmly in the grove, I've added 6x4 round magnet holes on the box and lid to make it more secure when we're on the go.