I was discussing gyroscopic forces and angular momentum with my two boys (7 and 9). I wanted to give them a cool demonstration, and give them a toy with which they can experiment to help grasp the concept. So we sat down together and designed this. They have been having fun with it all afternoon, and I will admit... so have I. Here is a video of it in action: https://youtu.be/dK1gNuUYlB8 I have included the STL's, and other CAD formats (naitive Solidworks 2018, STEP, X_T, Fusion360 import). Feel free to modify, remix, etc. Have fun.