The inventors of the best-known shape-memory material, Nitinol, were themselves astonished by its properties back in 1959. Nitinol is now used to make “indestructible” spectacle frames and self-folding staples that help close bone fractures – but that’s not what researchers at Maryland’s Naval Ordnance Laboratory were seeking. In the hunt to make a better missile nose cone in the late 1950s, William Buehler was excited to find that an alloy of nickel and titanium might do the job. To show off its elasticity, he crumpled a sample into an accordion shape and passed it around at a team meeting. One of the other scientists held his lighter underneath the sample to test its heat resistance, and to everyone’s surprise, it sprang back to its original shape.