7th Week: London 2012 Logo

Here's a pleasant break from revision... One of these logos is the real London 2012 logo. It cost (apparently) £400,000 and was designed by Wolff Olins (WARNING: Flash-based site, and the little HTML they use is buggy too). The other two were cooked up in about 10 minutes by readers of the BBC News website. Can you tell the genuine one? You may be unpleasantly surprised.