Here’s a rubbery idea. Once upon a time cars had ‘tyres’ made of solid metal and wood. Rubber tyres came around the corner pretty fast, but they too were made of solid material, which was not very good at absorbing bumps and liable to become sticky when hot and brittle when cold. Enter one Charles Goodyear. He discovered that when lead, sulphur and rubber are mixed together and then heated, the result is a material that snaps back to its original shape after being stretched. Flexible thinking, you might call it. Mr Goodyear’s idea went on to expand both the auto industry and his bank balance.