This is made for fun & physics demonstration.

You can also do it yourself! You need to print this part twice and then connect them together using thread.

Warnig: free cad model & .stl file is made little to small.

Please resize it in your slicer (proportionally) to achieve Z height about 60mm.

It is designed to print without supports.

Please see how it looks at: https://youtu.be/Ov28-FnwqUc