Dad reports:
Either I was way off base in my description or Tommy’s tick has evolved.
His index finger of his right hand points then revolved in a counterclockwise circle with little to no arm movement. Simultaneously his head spins in a counterclockwise circle and each of his eyeballs spins in a counterclockwise circle.
He does this for two or three revolutions then pauses and either continues his activity or repeats the tick for one more cycle.
This one is quite a sight.