An audio-oscillator feeds a phase change network with two outputs. The relative phase of these two outputs can be varied from zero to 180° and the amplitude of one of the outputs can be reduced to zero. One of these outputs is connected to the horizontal amplifier of an oscilloscope and to one of the traces of a dual-trace oscilloscope. The other output is connected to the vertical amplifier of the first scope and to the second trace of the dual-trace scope. The gains of the scope amplifiers are adjusted to give the 45° line of the x-y scope and equal amplitudes on both traces of the dual-trace scope when the two outputs of the phase change network have the same amplitude. Once these gain settings have been established, the relative phases and amplitudes of the two components are measured on the dual-trace scope and the pattern is observed on the x-y scope. To observe more complex lissajous figures only one output of the phase change network from the audio-oscillator is used. The second input is derived from a 60-cycle step-down transformer. (We also have a Cenco sand pendulum which can be used to illustrate the motion which results from the superposition of two perpendicular harmonic motions.)