John Voevodsky

You've heard of Frank Whittle, yes? Inventor of the jet engine. Thomas Edison? Electric light bulb. Leonardo da Vinci? Pretty much everything else. Except ...

John Voevodsky can legitimately claim to have saved hundreds of thousands, possibly millions of lives. He invented the third brake light. Voevodsky was actually a psychologist who studied the effects of driving on attention, testing a small, inexpensive gadget on 343 taxicabs in San Francisco. It turned out that fitting an extra brake light on top of the boot (trunk in some parts of the world) lid, or in the rear window significantly reduced rear end collisions occurring as a result of someone driving too close to the vehicle in front and not being able to see the regular brake lights.

Not to be confused with Vladimir Alexandrovich Voevodsky, a Russian-American mathematician whose work in developing a homotopy theory for algebraic varieties and formulating motivic cohomology led to the award of a Fields Medal in 2002. He is also known for the proof of the Milnor conjecture and motivic Bloch–Kato conjectures and for the univalent foundations of mathematics and homotopy type theory. Got it?

I added that paragraph to show that, whilst a third brake light is a simple, effective and easily comprehensible idea, there are things in our modern world which, like the Schleswig-Holstein Question, are understood by only three people and one of those is dead.

I'm off to do my afternoon motivic cohomology ...