This is a puzzle ring constructed from 4 bands. This type of ring has existed for hundreds of years and you can purchase them in different shapes, sizes and number of bands, both as puzzle pieces and as jewelry. I noticed that this didn't exist on Thingiverse so naturally I had to create one for everyone to enjoy. If you give up, solving it, YouTube has lots of videos how to solve it.
0.1 layer height, 0.4 nozzle
Print the ring standing up (as in the second photo). Set support material at 70-80 degrees to not have too much support material to break off after print. Unless you print at 0.25 layer height, you will need more support.
You cannot scale it any smaller, as the ring will be printed as a solid block, but you can scale it larger. It is best to print at 200% with 3 walls and 20% infill. Makes it strong and easy to work with.
I created the model in Blender and exported to STL. I used splines and carefully adjusted the four bands so they don't touch each other and have enough space to not get connected while printing.