A lot of people out there recieved a free filament spool with their Prusa i3 MK2(S). Consequently a many should also have an empty spool of said filament. This idea was blatantly stolen from here.
The Prusa filament spools already have holes in them, so I just reused those instead of drilling new holes. You can use 1.75mm filament as rivets but 2.85mm filament would work best.
You'll need around 100g of PLA per 90° so 400g to complete the circle. It prints nice with 0.35mm layer height.
I'm not sure where you'd use the tall boxes for, but I uploaded them regardless. Since the Prusa spool is very wide, in my opinion splitting each segment into three boxes makes more sense.
I printed it with 3/3/2 (1st, top, perimeters), which means that the bottom is completely filled.