Reminds me of a painting by Escher. People going up and down a staircase simultaneously. The French have a term, creative as they are, "l'esprit d'escalier", or the spirit of the escalator. L'esprit de l'escalier (staircase wit) is thinking of a clever comeback when it is too late. The phrase can be used to describe a riposte to an insult or any witty remark that comes to mind too late to be useful—after one has left the scene of the encounter. The phenomenon is usually accompanied by a feeling of regret at not having thought of it when it was most needed or suitable. How often have you passed someone on an escalator that you wanted to speak to, but only thought of what to say afterward. The moment is gone forever.
