Simulate a spirograph in blender

Hi guys!

I found myself doing a somewhat chanllenging task, trying to simulate a spirograph in Blender;
like this one:
I am currently completely stuck at the fulcrum (the left part at 4:00, which lets the arm slide through)
Anyone has an idea how to solve this in Blender?

Thanks !

Wheel on the right is turning.

handle bone parented to wheel bone.

Arm bone parented to handle pointing at fulcrum.

fulcrum bone 2 copy rotation of arm bone.

Interesting project! I’m glad I saw that video!