I like this 3d printed one too: https://youtu.be/7hUonUE1hEY https://youtu.be/7hUonUE1hEY Similar principle - separating the input and testing phases, but uses

I like this 3d printed one too: https://youtu.be/7hUonUE1hEY https://youtu.be/7hUonUE1hEY Similar principle - separating the input and testing phases, but uses an interesting binary ball bearing approach.