Marble bearings (aka: Simplest filament holder ever)

*** Updated: I took Austin's advice and added a top to enclose the marbles since some filament spools aren't smooth enough to rest on the marbles alone. I also took out some faces so they would slide better when nested.****

I wanted a filament holder that wouldn't result in yet another thing crowding my desk. If your desk lamp has a skinny pole and you can figure out how to take it apart why not use the lamp to hold your filament?! Print one of these, fill with marbles, put your filament