Algorithms from the “Book”
Nature's primary algorithm is massive parallel computation, at a scale that beggars us all."The Book" is all around us.  The algorithms that nature cares about are woven into the fabric of the physical world.  Our algorithms are just poor approximations, intended to make simulation tractable on discrete computers.For example, this site occasionally carries posts about making water look realistic in games.  Those posts usually acknowledge that the graphics approach they describe is cheating compared to actually solving the Navier-Stokes equations.  But the NS equations are just a mathematical expression of reality.  We then cook that mathematical expression down even more, in order to arrive at a collection of algorithms (finite-difference approximations, domain partitioning, numerical solvers) that attempt to embody the math.Yet problems that today we would consider impossibly hard to solve computationally-- for example, fully resolving the flow of water around a sailboat, not to mention the wind in its sails, and the stresses in the mast-- nature solves billions upon billions upon billions of times a second.