The rapid development of technology has allowed computer simulations to become routinely used in an increasing number of fields of science. These simulations become more and more realistic, and their energetic efficiency grows due to progress in computer hardware and software. As humans merge with machines, philosophical concepts and theoretical considerations on the nature of reality are beginning to concern practical, working models and testable virtual environments.
During this talk I will demonstrate and compare two models in computer simulation: cellular automata and three-dimensional creatures, Framsticks. I will discuss how simulation is understood and employed in computer science today, how software, hardware and the physical world unify, how simulated realities can be embedded one in another, how complicated it can get in application, practical scenarios, and the possible consequences of these situations. I will review a number of basic properties of worlds and simulations in such multiply nested structures, and will explore potential relationships of these properties with a level of civilizational development.