nostr:npub1ptmc89knq87ntjwhcehfzexgu6uvfjh3skrtn2pkcc60smljm5ys696rn8 

They're structural. They have tensile strength. It's what makes them obviously not blood clots.

They can be pulled out of veins.

My mother had a friend who had a 3-inch long one pulled out of an artery in his neck, and lived.