https://gitlab.com/kloppertje/balancingrobot
https://www.thingiverse.com/thing:2662828
https://www.ottodiy.com/
https://www.printables.com/contest/439-experiential-robotics-challenge
https://www.youtube.com/watch?v=6jzG-BMannc https://www.heise.de/news/Open-Source-Miniflitzer-fuers-Wohnzimmer-9991785.html