9 dots. Connect all 9 dots with 4 straight lines, going through each dot once and only once, and without the pen leaving the page (the lines are connected). The lines must be thinner than the width of a dot . If you know the answer, don't post it to early, let people have a go, and the answer isn't posted on my photobucket account this time! lol.

1 line isnt 4 lines though. The question asks for 4 lines. But I have amended the question to clarify

Um, maybe i'm missing something but that seems quite obvious? Will wait until the answer is posted before commenting.

It's easy peasy. Just think about the definition of a straight line. It's the shortest path between two points, but no metric has been defined in the question, so we're free to define that ourselves. Unless I'm very much mistaken, the discrete metric works, because that way, ANY path is the shortest path between two points.