It's a puzzle to be done with a pencil.
It can look like this:
With a solution like this:
Instructions for playing
NEW! (2/17) Play in your browse with the applet:
Applet Pages
Puzzle Pack 1
Puzzle Pack 1 in sheet form:
Sheet 1
Sheet 2
Sheet 3
Sheet 4
(Puzzle Pack 1 Solutions)
All puzzles and puzzle concept © 2009 me, Charles Borchert. Yay!