For the past three weeks, the Ravens' playoff run has been almost solely viewed through the prism of Ray Lewis's delayed retirement, and while the 37-year-old perennial All-Pro and team motivator is entitled to a proper send-off, he's been allowed to eat the scenery.

WSJ: Super Bowl XLVII: Preparing to Be Harbaughed

McCain's future, in large measure, will depend on whether the voters in Michigan see his words through the prism of Theodore Roosevelt -- the heroic victim of dirty pool -- or through the prism of Bob Dole -- the snappish temper tantrum of a sore loser.

CNN: Jeff Greenfield: McCain's harsh words

The team's invisibility cloak exploits this effect, and relies on a specific geometry comprising two prism-shaped calcite crystals glued together, such that they leave a wedge-shaped gap beneath in which objects can be "cloaked" when illuminated with polarised light.

BBC: Invisibility cloaking benefits from crystal-clear idea

Of course you can always fall for rural France in the traditional way - through the prism of hotels, restaurants and the windows of a car or TGV - but the options for visiting the countryside are so diverse it is a shame not to add a twist of authenticity to a trip.

BBC: L'Accueil Paysan: Bed & breakfast on a French farm