Summary

No sharp corners to hurt yourself.

Instructions

Print two times.
Open-side-down down worked best for me.

Instert a BB (4.5mm steel ball).

Use instant-glue to CAREFULLY join halves.
Trust me, having both index fingers glued to it sounds more fun then it really is.

Paint it, write on it, or modify the file and include numbers in the print.

Note: thinnest part is 0,6mm, it might not print well on some settings. Perhaps if you scale it up 10% you will get better results. But it's basically just 6 spheres combined with a larger sphere, then enclosed by a big sphere, and finaly cut in half. A free cookie to the person who will create a parametric version! ;-)

Round dice (11.8mm) using a BB