Well, when traveling on the St. Johns River back in about 1971, we stopped to look into some blue pools that line the St. Johns like little blue arms. We saw eddies of water--water moving back against the general flow of the water--linear rivulets caused by heaven-only-knows-what. Contrary motion. Yes, that's how I think of eddies. But I just hadn't realized that eddies are generally circular. Today I've learned that my own immediate experience of eddies' moving in contrary motion to the general flow had been atypical and that, in fact, eddies are most often circular. I haven't ever seen a circular eddy although I have seen whirlpools caused by drops in water in streams. Are those eddies, too? I doubt it.