Figure 6. An analogy for simulated annealing. The ski slope is the cost function. It has local minima (snowbumps) and a global minimum to be reached (finish flag). The skier has to occasionally ski uphill (or "tunnel through the snowbumps!") in order to avoid becoming trapped in a local minimum. The technique gets its name from the slow cooling of a solution in which the crystalline state is the global minimum and local minima are amorphous states. The grains referred to are the elemental changes in beamweight.