When, geometrically, do you know you have BI?

[referee99]

Originally Posted by JRutledge

The backboard has nothing to do with that. There is not point on the back board that has anything to do with this kind of call. And the ball must be on the cylinder to have BI if you are not touching the ball. And if you are touching the ball, the ball must be above the cylinder.

Rut, if the ball was pinned by the defender on the gaudy red X in the image in the OP, can we agree that the defender may be touching the ball while the ball was in the imaginary cylinder with the basket as its base?