Clarification, here is a picture with each line segment as a different color:
Draw this picture on a piece of paper and do the following:
Without lifting your pencil, cross each line segment only one time. (there are 7 vertical and 9 horizontal line segments to cross) Good luck, and yes, it's possible, just like my
other riddle.
Edit: Okay, just to clarify, "to cross" means exactly that, so no you can't cross two segments at once by going through a corner, and no you can't trace lines. Enjoy.