Three pieces assemble into a 6-sided die (30 mm cube). Print one copy of each piece. No supports are needed. I don't recommend re-scaling the pieces, the fit of the puzzle will change if you do. The model at 100% can be tight at first, but should loosen up with time.
Assembly is not hard, but when assembled the die should hold together. The pieces may seem loose, but you should be able to cast the die repeatedly without it coming apart. There is a trick to taking it apart, but brute force works too. It may become looser over time (especially if you take it apart with brute force).
Three finishing options are available. Easiest: fill in the pips using a marker or pen. This looks lousy, as you can see. Better to just leave them alone. Second: use a hole punch to create circles and half-circles, then glue them into the pips. If you have stickers, you can punch them into 6 mm circles and half-circles and stick them on. Hardest: 3D print the pips and glue them in. You need 12 full pips and 18 half-pips. This looks the best, but the gluing takes a while. It can also be tricky to print such tiny parts.
The author hasn't provided the model origin yet.