COURSE OF PROJECTIVE GEOMETRY

§ 22:

*O83*

Choose two points *A* and *B* on k, and let *M* be the intersection point of *AB* and *l*.

Choose a new point *N* on *l*, and let *C* be the intersection point of *AN* and *k*, and let *D* be the intersection point of *BN* and *k* .

Then *L* is the diagonal point of the complete quadrangle *ABCD* that is not lying on *l*.