Reinventing the leg
I have found this a few times, building a giant hand for CHaOS, where the how the tendon attachments worked turned out to need to be very like the anatomy.
I am working on a system of model electronic neurons, and am looking at inputs for them, in particular light inputs. The problem with ambient light, is that it has an immense range, an overcast night is around a billion times less bright than a sunny day.
When you get a biological analogy right, it can almost be spooky, I remeber demonstrating CHaOS's giant hand and resting my hand on the fingers as a child was playing with it, and because it was moving in a natural way, some switch in my brain flipped into thinking of the hand as a living thing, even though it looks far from it, that is when you know you have done something right.