Making flexible circuitry is difficult because logic circuits are traditionally made of transistors etched into a crystalline silicon wafer, which is rigid.

ECONOMIST: Just press print

Since they are built on to a flat wafer, rather than etched out of it, layers of vertical transistors could even be constructed on top of one another, raising the intriguing possibility of multi-storey semiconductors.

ECONOMIST: Transistors: A tall story | The

The balance spring is etched out of a thin silicon wafer using a photolithographic technique, similar to that used for microelectronic chips, so its exact shape and thickness can be more carefully controlled than with metal.

ECONOMIST: A luxury watchmaker is putting silicon in its timepieces