“Muscular hydrostats” are cool. 😎 Tongues, elephant trunks, and octopus/squid tentacles are the classic muscular hydrostats. Basically, you can change the shape of a “water balloon” by squeezing it — and a tube full of muscles is like a water ballon that can squeeze itself into different shapes. Kooky. Strange that I’ve spent 23 years regularly thinking about muscle tissue and didn’t know how tongues stick out, or how an elephant trunk works. Oh well — better late than never, I guess!