'Theme 6-6 is the sixth level of Danger Above .
If one is to wait for a while, one of the helmet pigs will start to roll to the right.
Strategy
Launch a Boomerang Bird. with perfect timing, boomerang it into a stone brick on the upper "cannon" to ram the stone into the TNT, killing the Medium pig. The Boomerang Bird should now fall on top of the Helmet Pig sitting next to the bottom "cannon" a stone triangle should fall and hit the "cannon," causing the TNT to activate and finish off the pigs.