We all represent examples of self-organised and self-assembled structures. The natural world is full of them, and they are by no means exclusively biological in character. One can think of, e.g. the process of crystallisation from a melt or saturated solution, the hexagonal patterns that form in Rayleigh–Benard convection when a fluid is heated from below, chemical waves, and patterns in Langmuir monolayers at water–air interfaces. Sometimes there is a fairly direct connection between the character and symmetry of the underlying intermolecular forces and the resultant macroscopic structure, and this will usually be true under equilibrium or quasi-equilibrium conditions. Such processes can be analysed and modelled using free energy functionals and relaxational dynamics. Often, however, the structure arises under nonequilibrium conditions, where there is a continuous flow of energy and/or matter through the system, in which case more sophisticated approaches are needed.