Yeah, but in the case of water the environment is what stimulates the change. Heat the water or cool the water, it changes.
In order for the analogy to hold and to have three seperate people in Heaven (outside of our physical universe) the conditions would have to be altered in three different ways.
It does hold up for say, manifestations of God on earth, for example the holy spirit of God being altered by the physical universe.
Now why did you have to go and drop that dirty rag in my nice sterile analogy? Lol
I doubt God is water in a solid state, the point is, that we have a substance right here on earth, that demonstrates what we ask ourselves, how could God be three distinct persons in one.
The more I think about it, the better I like it. JH