Figure 1.

Phase portraits—geometrical representations of trajectories in dynamical systems with different attractor types (with or without vector fields). A phase portrait is a plot of the trajectories of a dynamical system. Colour-coded slope or vector fields represent the rate of change of the trajectory at that point with respect to time—deep red indicates high rates of change and dark blue indicates low rates of change. Examples of trajectories for different initial conditions are shown in black. (a–d) Produced with Phase Portrait Plotter [26]. (e) XaosBits at English Wikipedia, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=732841. (f) The Lorenz attractor is an example of a strange attractor [27].