Triangle wave

The triangle waveform looks similar to the sawtooth. But it is smoother. You can also describe it by linear functions. The wave slowly rises to 1 and then goes down to -1 and back again to zero. So if you draw a straight line at y-position -1, you have a row of triangles. Its sound is very smooth and near to the sound of a sinewave. But a little more metallic. You can build a triangle by additive synthesis, empoying sine waves. Take some odd harmonics of the base waveform and add them a little bit quieter.