Gentle on people and gentle on the pocket book. Taking cues from the 40,000 muscles and unique agility of an Elephant's trunk, Fraunhofer Institute for Manufacturing Engineering and Automation in Stuttgart has developed the ISELLA prosthetic arm. Two motors per joint help prevent undesired motion and an interesting drive system uses a high-strength cord wrapped around a double helix drive shaft. It's claimed that the drive system is more energy-efficient than a typical geared setup, has a high strength-to-weight ratio, and is more cost-effective to manufacture.