Simple, Elegant, Deep
I actually found myself thinking of this in symbolic terms and feeling a kind of spiritual understanding upon completion of each level. The idea is so basic, it is almost like playing with the very forces of nature. You must use harmony and balance to achieve your goals, learn where to share your energies and where to hoard them. I don't think it is entirely obvious, but there is an unspoken, perhaps unintentional message inside of this clever little game. It is also just kind of fun to play with.