Theme 21-11 is the 11th level of the second page of Bad Piggies, in the game Angry Birds.
Shoot the White Bird at the stone brick below the nearest tower at the slingshot. This should knock over the tower. Then shoot the White Bird at the Stone Brick holding the stone bricks and TNT from the pigs. Use another White Bird to kill the last pig. You should get 10000 points from the remaining White Bird.