This is a Double Pendulum Desk Toy

See it in action here: https://vimeo.com/877763489?share=copy

It is fascinating to watch, the two balls take turns to dance one slowing to a stop as the other increases its speed. :)

I have attached two versions the one in the video needs supports under the balls and also under the little square connectors and you need to be very gentle when you remove them. The other version only needs supports for the balls so its an easier print.

Print at 0.3mm layer height, you should see the strings in the print preview. If using Bambu Studio set your wall generator to Arachne.