This final chapter is a short introduction to pattern-forming systems, which highlights a few concepts and models rather than pretending to give a general overview (which is impossible in 40 pages). We focus on stationary bifurcations, distinguishing between scenarios where the critical wavevector vanishes and where it is a finite value, because they have different nonlinear behaviors. A few pages are devoted to describe some different experimental setups: thermal convection (a fluid heated from below, showing the rising of convection cells); unstable growth process (under particle deposition, with the formation of mounds); and a rotating mixture of granular systems (with their phase separation).