During the Night at the Barn chapter, once you’ve linked Sarah and Grandma by their eyes, arm sleeves, and waist, their ribs will now retract from their lungs and you can complete the Lung Puzzle. Once you complete the Lungs, you can complete the Heart Puzzle.
Video of this puzzle can be seen here: Lung & Heart Puzzle on Youtube
Once the ribs retract, you can see that each set of lungs has branches pointing at symbols and symbols on leaves. The goal is to make sure the branches in Sarah’s lungs are pointing at the symbols found on the leaves in Grandma’s lungs. And vice versa. Just click on a branch to move it.
Once you’ve lined up the branches in the lungs, they’ll back out and you’ll be ready to complete the Heart Puzzle. The Heart Puzzle for both is just the old fashioned Memory game. Match the flowers to complete it. Don’t forget to do both Sarah and Grandma’s Heart.