IT BEGAN JUST before Christmas with the startling discovery that Paul had lined up all his toy cars in one long, winding path across the living room floor, just like in the old days.
“Oh, no! Paul, what is this?” I cried, unable to hide my dismay. It had been at least four months since I’d had to watch my feet for trip lines of vehicles.
“Cars,” he answered matter-of-factly.
I wondered whether he had been exposed to a forbidden food somewhere, but that kind of reaction should have faded within a week at most, and the lines persisted. Then behavioral issues started to creep in as well, mostly connected to routines. ...