The basic idea behind most of these figures is the Lissajous Curve though this curve itself is never traced explicitly. Instead, we iterate over points along the curve and at each point draw a straight line (of various lengths and varying colours). We also allow this line to rotate with time. The variation in the figures displayed comes from varying the relative frequency of rotation and the controlling frequencies of the Lissajous Curve. If, for example, we choose many points along the basic curve and a slowly rotating line we do not see the image as overlaying lines but as caustic curves. As with the mechanical harmonograph that inspired these experiments, allowing the scale of the figure to decay over time produces effects more interesting than retracing the same figure again and again.
A number of elaborations on this idea move the figures away from any obvious relationship to the original curves.
