[eggy]

I recall when I was building animatronics in the 90s there was a pneumatic air bladder "muscle" at the time wrapped in stainless steel weave basket. So instead of using a rigid cylinder with rod, when you inflated the bladder its length contracted. You could make an arm bend and the appearance of a bulging bicep! Somewhat similar principle, but animatronics doesn't use high-volume parts, so it never took off. These origami-inspired actuators seem really cool!