I explore simple natural physical systems that exhibit useful, interesting computational effects. I view such physical systems as specialized “computers”/natural–computers. These natural–computers (physical systems), as they evolve in phase space, can be seen as performing a computation or executing a natural algorithm to solve a specific problem. In particular, I consider physical systems that apparently “solve” problems that are hard to solve by using conventional computers. I view the physical systems themselves—not their numerical simulations—as computers. I discuss three main ideas: A gravity powered “computer”—constructed out of beads and rods of an abacus—that can perform data processing tasks like sorting, searching, etc. on an unsorted database; Bilateral Computing paradigm for the construction of natural physical computing devices, whose operation blurs the distinction between computing and inverting a mathematical function; Balance Machine, a generic natural computational model that is shown to be computationally universal.