The object of this simple but difficult online strategy game is to encicle the cat with dark green tiles. Every time you click on a tile, the cat hops. Can you surround him before he hops off the field?
Man... This Games is called "Chat Noire", not "Circle the Cat", and is one of the oldest Flash games I've ever played. Its more than 5 years old (16 Oct 2007)!
I remember playing this Flash game a few years ago - I think we featured it on Neatorama but I couldn't find it on the blog. Anyways, the trick is to goad the cat into an area where you already have circles filled. That way, you have more ways to circle the cat. Depending on the starting conditions, there may just be no winnable solutions (for example, if the cat is out in the open)
Check out the original site from gamedesign jp:
http://www.gamedesign.jp/flash/chatnoir/chatnoir.html