This is a strip from FoxTrot comics, which is written and illustrated by Bill Amend. It was carried by more than 1000 newspapers worldwide. From it's inception in 1988 it was published daily until December 31, 2006, when Amend switched to a Sunday-only format. Detailed information about characters and the themes of the comics you can read in Wikipedia.
This strip shows us impossible triangle. It was issued July 05, 2006.
Official FoxTrot site http://www.foxtrot.com
The image was found at http://www.gocomics.com/foxtrot/2006/07/05