You are declarer, as South, in 6♣ in a team game. West leads the ♦K. You win the ♦A and play the ♣K, both opponents following. If you find the proper line of play, you can claim. See it?
Draw the last trump with the ♣Q, cash the ♥A K and play the ♦J, discarding the ♠3. West, who you know has the ♦Q from the opening lead, wins the trick, but is endplayed.
A spade return will run into your ace–queen tenace, while a diamond return will allow you to ruff in dummy and pitch the ♠Q from your hand.
What about a heart return? If West leads the ♥Q, you can just ruff in the closed hand, cross to dummy with the trump ace, and pitch the ♠Q on ♥J. If West instead tries to get out with a low heart, cover it with the jack. If East plays the queen, the heart suit was 3–3: Simply ruff, cross to dummy and take a spade pitch on a good heart.