It looks like it could be pretty easy to make. You just need a base with the stacker. Maybe make it out of foam covered in fabric, or use some interfacing to make it really stiff and stuff it tight. If you use foam maybe a square for the base with a circle in the center cut out and another peice of foam cut in a long roll to stick inside the circle for stability....clear as mud?
If just making it stuffed you need a long stuffed tube that you can maybe some how attatch at the center to a base, maybe like a bean bag base so it will stand and not tip? Then just make some stuffed rings in the different sizes. Those should be easy...basicaly just make doughnuts, same size center hole (unless you make it cone shaped) with just differnt widths for the different sizes.
Ok so Im not making sense, I can see it in my head on how to do it and cant think clearly...sorry its late...hope you find something that works
