The Meaning of Life, the Universe, and Everything.
If anyone out there is interested in making Minecraft Map Art I have produced a video which will explain why you only need 50 of the 455 Minecraft blocks (currently in 1:14:4).
Hope someone finds it helpful and informative. It certainly surprised me when I discovered which blocks look the same or totally, unexpectedly, different in Map Art. You're bound to be surprised by what I discovered.
I really hope that I will save someone some time working out what took me three weeks to discover.