The shapes of soundwaves

This afternoon Simon gave me an introductory lesson to soundwave shapes: triangular, saw tooth, ramp, pulse 0 to 100% duty cycle. It turned out he can imitate all of them easily, and that is next to his perfect pitch. Recently at a construction site he heard a truck buzzing and screamed: “F sharp in the highest octave!!” Well, now he can also say which wave shape that was.