I have a math puzzle I just came up with. A mesh is formed by 3 sets of parallel lines on a plane (2D surface). Each set contains an infinite number of lines with a constant, perpendicular distance between them, and each line is infinitely long. My puzzle asks that you find an expression for the average number of intersections per area.
Here is a link to my puzzle: http://ericboy.wordpress.com/2012/08/30/mathcritical-thinking-puzzle-83012/. Please let me know what you think or if you have any questions.
Thanks, and Good luck!