It is convergence when evolved independently. Like how different crustaceans evolved into "crab" [1].

If everyone is under the same feedback, like the London wobbly bridge [2], it is more like reacting to external force, for a lack of better term

[1] https://news.ycombinator.com/item?id=31615200

[2] https://en.wikipedia.org/wiki/Millennium_Bridge%2C_London#Re...