Point the other way as lead "mechanic"
 

Anyone know the origin?

I thought the signal was to start the shot clock.

could be but I've seen it right after a made basket when the ball is dead

Sometimes it looks like they're pointing the other way and other times it looks like they are signally two points. Do you see it after made 3s?

Either way, its wrong. There's no signally by the lead needed and certainly no ruling on possession by the official that isn't preceded by a dead ball or stoppage of play.

Supposedly Irv Brown, the Colorado Sports Announcer. He worked 6 NCAA final 4's back in the 70's. Seems like 4 of those were the actual finals. I also believe this was mentioned in an old Referee Magazine article when they did an interview with him back when Referee was just starting. Someone who has all their old Referee Magazines articles from the beginning can probably confirm this.

Its a pro mechanic in the NBA rulesbook called "Direction of play" with instructions "Point - direction, call team color"