Problem of the Week 868

Spear the Points

What is the greatest number of lines you can draw through 16 points so that each line contains exactly 4 points. You may place the 16 points anywhere in the plane you wish. (A line is doubly infinite.)

[Source: Noam Elkies in Horizons, Sept. 1998]

© Copyright 1998 Stan Wagon. Reproduced with permission.

The Math Forum

2 October 1998