It was attempted to use planetary gears to realize the mechanical implementation of postural synergies since it might provide better accuracy than differential pulleys and might be easier to fabricate than designing a differential hydraulic system. Then the synergy outputs will be rotations (instead of being translations as in the other two options). The most direct way to connect these synergy outputs to the finger joint axes is to use flexible shafts. What's more, rotations of these flexible axes would not be affected by a possible presence of wrist motions. Using worm gears and gears, rotations of these flexible shafts drive all the finger joints.