There is now an updated (WIP) version of the simplified STEMFIE desktop catapult, which you can download from this link as a Blender file and ready-to-print .3mf file.
This is the official homepage of the STEMFIE Project – the 3D-printable and open-sourced educational construction toy you can download and make at home!
This toy is not suitable for children under three years due to the choking hazard!
.... is made for you!
... is open source.
... is free to use and adapt.
... has no fees!
... is #MadeWithFreeCAD
... is easy to 3D-print
... is upscalable (200% - 500%)
... is lots of STEM fun for kids!
... is ready for you to download