An amazingly simple, and ridiculously useful and successful mechanism that converts linear motion to rotational motion. It’s basically what allows us to take a force produced by, say, steam, or an explosion, and make a wheel turn. Stick a few of these together and time the rotation of each correctly, carefully controlling the explosions and the exhaust and you have an internal combustion engine that powers our cars. There’s a lot amazing to me about it, but I am still impressed with how effectively it takes something moving back and forth, and makes something spin round, and vice versa.

The piston

The half-life of caffeine.

For a closer look next time you’re at the beach. Pay close attention to whether you find one with a dextral or sinistral aperture.

Gastropods are the largest class of molluscs which includes limpets, snails and sea slugs. For those who weren’t sure.

Info from Discovering Sea Shells by Barry Charles

Typical gastropod anatomy