Optimus hand/forearm engineering represents majority of robot difficulty; Tesla solving for 27-28 degrees of freedom with custom tendon-driven design mimicking human biomechanics

“Right now, we're struggling with the the final design of the hardware. Like I said, it's really primarily the hand. Not to just just dismiss the rest of the robot. The rest of it's also uh important, but but the hands are the hands inclusive of the forearm are a majority of the engineering difficulty of the entire robot... your hand is kind of like a like a like it's like a puppet. The mus the muscles are coming from the forearm and they're pulling the tendons... I think that the human hand is something like depending on how you count it, 27 or 28 degrees of freedom per you know in in the hand.”