Hahahaha, just being silly up there! =P
The most interesting part of it is what it says on his Mocpages' page for it:
This piece uses another new palette I've been working on. The palette uses transparent red, yellow, blue, green, orange, and black over top of all of the readily available opaque colors for a possible total of about 180 colors. Some I don't include though due to cost [in the case of dark purple and pink] and there are many colors that are too close to each other to bother using so I choose one. Anyway, in this pieces there is a lot of transparent green although you see it as a lighter shade of black.
Which is incredible!
For more of Doug's fantastic mosaics visit his website, here.