Shape Memory Materials are usually Alloys or Polymers that have shape retaining properties. Shape memory materials are strong, lightweight alloys that remember their shape. Shape memory materials work by rearranging themselves in a reversible manner every time they are used. They can change between different forms every time they are used depending on how they are sat on. Shape Memory Alloys and Polymers are often used in seats and beds for maximum comfort. These were also used on the space shuttle and in airplanes to remeber the positions of the flaps and ailerons.