Plethora

South leads the K, and north follows suit.
East to guarantee a contract of 7.

Dummy discards a diamond as east wins the A.  A trump is led to dummy and the small spade is ruffed.  Another trump lead is followed by a ruff of the Q.  Trumps are drawn.  East discards the A-K on the last trump and the A.

Trap: discarding a spade at trick one would leave declarer unable to shorten his trumps sufficiently; he would be at the mercy of opposing red-suit voids.  Also, it is possible for the A to be ruffed by south, so it cannot be cashed prematurely.