I experimented a bit with making filament from PET bottles, looked for a way to spool plastic straps. I tried the original model but it wasn't sturdy enough.
So I made a stronger version, but kept the hexagonal interior, to allow integration with a motor, crank, etc.
Also added a two-sided center hexagon, to fix one side onto some kind of mount for stable winding.
The author remixed this model.
I redesigned the whole thing, but was heavily influenced by the idea of the original.
New spool is sturdier, bigger, but the inner hexagon hole is compatible.