when you shine a light between the reflections of two things harmonizing to the same frequency, small disparities in rhythm may be observed.
these occur because of the relative difference in rhythm received between observer and harmonic points.
this isn't to endorse relativity, a sick combination of morality and pretense.
but this is to point out the following, in logical syllogism:
Please act accordingly.
in fact, some might say the lissajous patterns resemble light as observed from the bottom of a pool in twilight in summer.