Make a 3D printed Rover complete with pulley motor. via instructables
This 3D printed creature can be simply clicked together with one and the same printed lock washer type. Just in case you want to convert it into a 4D version, you can add a motor (pulley is in the files)
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.