Total angular offset between the first and last pendulum, on a log scale.
Which pair of state variables the square plot beside the chart shows.
Drag either white bob to pose the pendulum. Changing an angle, mass, length, gravity, damping, count or spread re-releases the pendulums from rest. Shortcuts: Space pause, R release again, T trails, S save image, P next phase plane, [/] previous or next preset.