[color=#0000ff][i][color=#0000ff][i][color=#999999]This activity belongs to the GeoGebra book [url=https://www.geogebra.org/m/mes4bgft]The Domain of the Time[/url].[/color][/i][/color][/i][/color][br][br]By combining [b]two [/b]SHM with perpendicular directions, having the same period and in the same phase, we get a straight line. If we shift their phases, we get ellipses. If they also have different periods, we obtain [i]Lissajous curves[/i].[br][br][b][color=#cc0000]As we will see later, the motion of a pendulum with a sufficiently small amplitude is almost identical to SHM[/color][/b]. Therefore, the combined action of two perpendicular pendulums also produces Lissajous figures. These devices are called [i]harmonographs[/i].

[color=#999999][color=#999999][color=#999999][color=#0000ff][color=#0000ff][color=#999999][color=#999999]Author of the activity and GeoGebra construction: [/color][/color][/color][color=#0000ff][color=#999999][color=#999999][url=https://www.geogebra.org/u/rafael]Rafael Losada[/url].[/color][/color][/color][/color][/color][/color][/color]