Yet another filament spool holder - Modular

This spool holder has module-based supports that allow various spool height depending on the number of modules.
The horizontal length is fixed (8.5 cm), but I intend to provide a modular solution as well, as soon as I find a suitable way to support the spool weight (do not hesitate to provide suggestions in comments).

I designed it to use less than 10cm parts, so that my PrintrBot simple can print it.