This is an updated model of my tic tac toe design: https://www.thingiverse.com/thing:2980796.
This other version allows for you to attach the lid with rubber bands for travel.
This new one is designed to have a lid, so the base has been revised.
STL's attached are in mm, and tolerances for 3d printing are already included (so there's no need to scale up/down).
Make sure to like and post a make!
Picture credit jayjr1105