Once you strip away your muscle, bolt three big gears into your shoulder. One makes your arm swing forward and back, one lifts it out side to side, and the other spins it in a circle. At the elbow, run two steel cables like strings. The first pulls your forearm up while the other pulls it back and down. Then add larger gears to make it bend smoothly. Inside your forearm, add a planetary gear set that twists it left and right,
