Occasionally we should consider a more accurate representation of the possible ball flights directly to the front wall. The front wall triangle is very useful. But what that image does not portray is the 3-D reality of the front wall. The triangle does not provide any clue about the distance the strike point is above the floor. A ball flight can be drawn to the right front corner, but there is no clue if the contact point is just above the tin or just below the upper boundary line.

To represent all the possible fair shots to the front wall a 3-D image is needed. The 2-D image is a triangle. The 3-D image is a pyramid.

To construct the front wall triangle the coordinates of the ball must be known; x-y coordinates. The usefulness of the triangle is based on knowing the extremes; how far to the right and how far to left can a flight be and still hit the front wall directly. Every ball flight between the extremes will also reach the front wall. But the third dimension, the height of the ball flight above the floor is ignored. In most situations it is not important to know the height of the ball flight.

For the 3-D image, a pyramid, the extremes must be defined. Instead of a single point in the right side corner it is the entire crack from tin to upper boundary and similarly for the left side. In addition, the extremes of height are defined as a fraction above the tin and just below the upper boundary. The apex of the pyramid is the strike point defined by traditional x-y-z coordinates. The base of the pyramid is the entire fair surface of the front wall. Connect each corner of the pyramid base to the strike point of the ball. There you have it, the front wall pyramid. If any part of a player is within the volume of the pyramid, they are interfering with ball flight to the front wall.

Is it possible for an opponent to be within the front wall triangle and not be interfering with a front wall shot?

Well, yes. An average player who hits the deck will be below the 17 inch tin. Connect the dots. Height of the strike point to a point just above the tin. The player could be in the triangle and yet not be in the volume of the pyramid. No ball flight interference.

A less extreme action to avoid ball flight interference is ducking. In many instances the ducking doesn’t avoid ball flight interference. It is most likely to come into play when the strike point is well above head height. Again, connect the dots. Strike point of the ball, at say 8 or 9 feet, connected to a point on the front wall just above the tin defines the boundary between interfering and being clear. The pyramid is needed to help make the correct decision.

Because these are unusual situations there is little experience or expertise to make the correct decision. A recipe for a battle of opinions when they do occur.