dynamical equilibrium

I was challenged today to provide examples of dynamical equilibrium

I mentioned that riding a bicycle is an example.

Later, it occurred to me that the Red Queen theory is another example.

A UCLA math prof seem to argue that dynamical equilibrium is a oxymoronic word, 'homeostasis' implies stationary.  To his critique on stationary interpretation of homeostasis, I disagreed. I offered the predator-prey model as an example of dynamical equilibrium.