Starting at the top left corner and going clockwise the colours are as follows: Medallions, Trax, Raving Mad, and Melt my Heart. Trax is absolutely my favourite MAC eye shadow and is the only one that is still available. Melt my Heart is still available in the Melt my Heart quad, though. There are lots of comparable shades even at MAC for the discontinued colours. What are some of your favorite MAC shadows? What would be in your quad if you could make one?