I wonder how long it has been since you had a good look at the back of your hand? I took the time to inspect the back of my own left hand not long ago, and found it to be strange and unfamiliar territory. The hairy lower-left-hand corner was divided with uncanny precision from the remaining portion, a larger and quite bald quadrilateral across which several veins, prominent yet disturbingly delicate in appearance, meandered in random loops and curves. Several spots and blemishes and many dozens of wrinkles were new to me and the whole expanse seemed much older than I remembered it. If I were to be dropped in the middle of a vast simulacrum of this landscape without guide or compass I am sure that I would be completely disoriented and yet this very fantasy is often used as a bold assertion of one’s navigational skill. Of course, it may be that I am unusually ignorant of the backs of my own hands. For all I know my readers would be able to quickly render a schematic diagram of their own from memory. Although the only way to put this theory to a rigorous test would be for you to try the experiment with your hands tied behind your backs, drawing with a pencil held in your teeth, but I think that we may dispense with such drastic measures as we are all friends here.