Notice?
When Dumbledore fought Voldemort, notice they used EACH OTHERS' elements. The house of Slytherin's element is water, and Gryffindor's is fire. I think this is all at once, simple, brilliant, and ironic. (BTW, Hufflepuff, of course, is earth-the yellow signifies wheat and Ravenclaw is air, as indicated by the blue.) Note the whistling sound Dumbledore's spells make, how he throws Harry back to safety, the furious gurgling sound Voldemort makes in the water. I think this was a brilliant scene.
Do you ever get down on your knees, and thank God you have access to my dementia?