Mathematical systems have the property that when iterated or integrated as appropriate, depending on their initial conditions, they tend to seek out a certain set of states called an attractor. In a map of the possible system states the attractor may be a single point, a collection of points, a curve, a collection of curves or a region with an intricate fractal boundary. An attractor that has a fractal boundary is called a chaotic (or strange) attractor. In fact it is often the case that multiple attractors exist for a system, each "owning" its own set of initial conditions.