History: We make ____ oscillators from only odd-numbered harmonics, and ____ from all harmonics.

We make __ oscillators from only odd-numbered harmonics, and __ from all harmonics.

• Square, rectangle, and sawtooth; Triangle
  Triangle is a gentle simple wave.
• Triangle, square, and rectangle; Sawtooth
  Yes!
• Triangle and sawtooth; Square and rectangle
  Square waves only use odd-numbered harmonics.
• Triangle and square; Sawtooth and rectangle
  Rectangle waves, while have a duty cycle, do not use all harmonics.