So in the video you first see a section of movement using the second and fourth axes. Then after that the arm goes back to zero (sticking straight up) and you s

So in the video you first see a section of movement using the second and fourth axes. Then after that the arm goes back to zero (sticking straight up) and you see the midsection rotate back and forth without the end section rotating. That’s the other two axes. There are also closer photos here: https://twitter.com/tlalexander/status/1455100498428588036?s=21 https://twitter.com/tlalexander/status/1455100498428588036?s...