Launch the Orange bird through the vertical wooden block in the top-left structure. As soon as the Orange bird breaks the wooden block, expand the Orange bird to push the structure to the right. With good timing, the right structure will also topple from the debris. In the video below, the two bottom pigs are popped, so reaching the top-right pig with the White bird is sufficient. If necessary, use Big Brother to detonate the TNT in the bottom-left.