Williams FW31 - rear diffuser 'hole' 04 April 2009
From this angle you can clearly see the controversial opening (in yellow) in the protested Williams diffuser. This brings more air into the central part of the diffuser, allowing it to work harder to increase downforce. Most rivals believe this hole to be against the spirit and/or wording of the regulations and the design's legality will be considered by the FIA's International Court of Appeal on April 14. Also note the small splitter in the central diffuser.