A waveform which appears (on an oscilliscope or in a waveform editor) as a series of rising and falling straight lines of equal slope, resembling a row of roof peaks or triangles without the base segments. In terms of its harmonic content, the triangle wave has a strong fundamental, much weaker and rapidly decreasing odd harmonics (much more so than the square wave), and no even harmonics. A pure triangle wave has a reedy, thin sound.