Turning Point Field set-up

Screen Shot 2018-05-04 at 12.35.50 PM.png

How are the 45 degree caps centered on the tile, is the mid-point between the points of contact by the ball and cap the center of the tile or is the ball on the center of the tile? From what I see the picture indicates that the midpoint between the two points of contact is the center of the tile, might just be some perspective distortion though.

the ball is in the center

Thanks!