" "Casting Stones" by Erik Tomblin features an old man, Lucas, who lives in a crumbling old house, doesn’t talk much although he listens politely, and follows a daily ritual of throwing a rock across the road at exactly 3:37 PM every day. If you ask him why, his response is the same as it is to almost any question, "Don’t know." Just a feebleminded, maybe slightly crazy, old man? But Lucas occasionally "knows things." When he deigns to speak, it’s often to make a prediction or pronouncement that’s worth listening to.
Andrew, Lucas’s closest neighbor, drops in to talk to Lucas from time to time, even though he knows he’ll be doing most of the talking. They become friends, after a fashion. The results of that friendship may leave you wondering just how mindless that stone-casting ritual is, and whether Lucas knows more than he’s saying. If I had a neighbor like Lucas, I would be very cautious of how I treated him."