Do those squared-off sections of the boxart look familiar to you? Well, the two that you can kind of see, anyway? I bet they do, but just incase you don't recognize them...



I bet you see the connection now! There's also a bit of Hylian script on the box that translates into the following...

Wisdom, Nehru, Power, Din, (obscured), (obscured)rol
This should give us an idea of just what's going on in Skyward Sword. Remember, the three goddesses are said to be responsible for the creation of Hyrule itself, and they left behind the Triforce when finished.