[used:)]

Just keep in mind that art isn't all about aesthetics. A big side of it is what the artists sees in his work and is trying to express.

Perhaps the glass full of water being an oak tree is to represent the amount of synthesism in our society today. Or perhaps making a reference to how much water is in all living things sending a bigger message of how at the base of it all, we are all the same components and should disregard the smaller, petty differences. Or perhpas he simply intends for the the viewer to be dumbfounded and find meanings in the work for himself. You have to think outside the box.