"Well there’s red ... for fire ... and Gryffindor, obviously. And blue ... and that was the colour of Ravenclaw. Raven ... bird ... Air ... this is getting a little spooky. So, what’s left? Slytherin wore green, and Hufflepuff yellow. But which is which? Snakes are serpents, they slither ... which is a flowing movement like water ... and they also had silver in their livery, which could be seen as liquid mercury ... which is watery. But what does that say about all my mercury markers? Should I have been a Slytherin? Urgh, let’s not think about that.