Gearbox- Build your Own- STEM
Build it, learn its history, use it. You may or may not know that a gearbox mechanism is used in automobiles as part of the transmission that provides speed and torque from a motor to the driving wheels. Ugear's STEM building, and then using, models are composed of high-quality wooden boards with pre-cut details. They include really well done instruction manuals as well as an App, if you want it.
As you assemble the gearbox, be careful not to bend or break any of the more than 100 wooden parts, but if you do have an accident, use UGears' website to request a free replacement. You also have the choice of painting the model, although this step will add a few days to the project.