We have just considered general wave behavior in one-dimension. However, most waves propagate in two and three dimensions. The added complexity comes with an added richness of phenomena that we can de...We have just considered general wave behavior in one-dimension. However, most waves propagate in two and three dimensions. The added complexity comes with an added richness of phenomena that we can describe. This includes sound waves and the phenomena of interference, beats, and the Doppler effect.