From McSweeney's:
After explaining my plan to my seatmates, I caught the attention of the bowler. I gave the signal, and the man at the head of our bench leapt into the air and crouched down again, followed by the second and third and so on. When we had finished, we started over. The bowler regarded us as if we had brain sickness, then began to snicker. Well, would you believe his next five tosses retired the side?[...]
Then came the exquisite sensation, which I have been fortunate to experience often, when inspiration presents itself like lightning. I realized that this human oscillation—I have named it the Wave—will function perfectly as a Jew alarm.
When one of the Hebraic horde is spotted on the street, a passerby need only leap into the air with arms raised, calling attention to himself; another Christian will notice and understand, and shall perform his own leap; after him another, and so forth. Thus rolls the Wave up the street until all good men are alerted to the Semite's presence.
Good God but I am excited! My mechanical Jew alarm, which vexed me no end, seems such a clumsy thing now. I realize I was not seeing the forest for the trees—the human body is the greatest Jew-detecting machine of all. The Supreme Intelligence never closes a door without opening a window.
Who knew?