" The next day he passed Alai in the corridor, and they greeted each other, touched hands, talked, but they both knew that there was a wall there now.

It might be breached, that wall, sometime in the future, but for now the only real conversation between them was the roots that had already grown low and deep, under the wall, where they could not be broken. "

― Orson Scott Card , Ender's Game (Ender's Saga, #1)