Spherical 4-Sided Die (D4) - working and fair!

Model for a spherical 4-sided die. I had one of these as a kid and it seemed almost magical!

Inside the sphere is a hole the shape of a typical 4-sided die. The points are aligned so that the weight of the inserted 8mm ball bearing causes one of the number to land up when the die is rolled. You need either an 8mm bearing that comes with the beginner kit, or just the 8mm steel balls, not both. I've included 4 choices for assembly pegs, depending on your tolerances and whether you want to press-fit or glue.

Note to beginners: this design leverages Bambu Labs variable layer height feature to make the top of the spheres smoother - check it out.

Here is a link to the shared TinkerCad file. If you ungroup the objects you can reverse engineer it to have whatever 4 things you choose. Like, for example, the initials of your family members :)

Safety reminder: round objects present a choking hazard, in this case that includes both the printed die and the steel ball!