Let , ..., be four planes in general position through a point and let be a point on the line . Let denote the plane . Then the four planes , , , all pass through one point . Similarly, let , ..., be five planes in general position through . Then the five points , , , , and all lie in one plane. And so on.

CITE THIS AS:

Weisstein, Eric W. "Cox's Theorem." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/CoxsTheorem.html