It was 8 extra large baseplates (Studs Out), 192x96 studs. It used 8 colors: white, black, 3 grays, blue, light blue, and sand green; all plates. I would have liked to have incorporated sand blue as well, but I only have those in 1x3 plate sizes, and, of course, 1x1s are what is needed for mosaics.
More information about this project is available at my B101.5 webpage.