The goal is to trace a line with your pencil across each edge on the box only once without crossing the vertices or picking your pencil up.

Note that this "box" contains 16 unique "edges".

Prove why this is an impossible task regardless of where you first place your pencil.

pcbouhid, I have heard of Euler through some educational years, but I can't remember who he is or what he's done. I can't even pronuounce his name (Is it oiler or yuler?). Sometimes I can barely remember Pythagorean's Theorem or Blaise Pascal's triangle. lol

I just like logic puzzles, and I think this one can be proved/showed with some pretty slick ideas and a concept. Maybe we both can be misunderstood sometimes. :)