Rex also has bionic ankles, which use a motor and spring system to mimic the actions of the human calf muscle and Achilles tendon, invented by Professor Hugh Herr who lost both legs to frostbite.
“I was climbing better with artificial limbs than I achieved before my accident with biological limbs,” he said.”Technology has this extraordinary capacity to heal, to rehabilitate and even to extend human capability beyond what nature intended.
“I think having normal bodies is boring…I have legs, you have shoes. If a fairy came and tapped on my shoulder and granted me a wish, would I wish my legs back? Absolutely not.”
(via Scientists build the One Million Dollar man - Telegraph)