Puzzle Ball with internal maze. Miniaturized version with a payload to fit 4 Australian $2 coins, hence the name.

Printing and assembly instructions - https://youtu.be/ZabESJmFGFc

Same assembly method applies, however it is much more difficult due to the smaller dimensions and relatively thicker walls. This version uses some print-in-place techniques for easier assembly. Supports required (conical support works well and saves material).