Throw in/backboard

[just another ref]

Originally Posted by BillyMac

All I was saying it that is was actually very difficult to actually observe, to within a few fractions of an inch, exactly where the ball hits, relying on one's peripheral vision, at best.

I say it is very difficult to observe within a few fractions of an inch, exactly where the ball hits, even if one is looking at nothing else. The direction of the rebound of the ball is about all you have.