Simple expandable spool storage

This is a simple design for a modular / expandable spool storage, allowing you to store spools upright without them rolling away. It is easy to expand and fits 1kg spools (roughly 200mm or 8" diameter). One unit fits the standard 1kg spool of my go-to store for filament, but mileage may vary with other manufacturers and personally I like leaving a little bit of space between rolls so I can grab them more easily.

Prints with no supports or rafts and very low infill.