During the course of your journey, you’ll obtain a certain, mystical musical instrument. When you play this among certain groups of Blessed Butterflies, a Goddess Wall will appear. Charge a Skyward Strike in front of it to start to draw on it.

Depending on what you draw, you can obtain certain rewards. You have to draw it all in one stroke by holding A, while moving the Wii Remote to actually draw. Here are the known drawings: