The scents are applied to the top of a cylindrical cage set on the edge of cropland.

WSJ: Out of Odor: Offensive-Smelling Bugs Put U.S. Farmers on the Defensive

In an effort to find out, the Pew Charitable Trusts asked my Tax Policy Center colleagues Eric Toder, Jim Nunns and Joe Rosenberg to set up something of a cage match: In the blue trunks, a broad-based VAT (think 9-9-9 only much less complicated).

FORBES: Deficit-Fix Cage Match: VAT Vs. Higher Income Tax Rates

This time a single rook was presented with the same tray-string set-up, while its pair waited in a neighbouring cage linked by a one-way flap.

BBC: Rooks team up to solve problems