As long as I’m discussing sound waves today, I might as well share some truly bizarre musical scores.
Faerie’s Aire And Death Waltz (from “A Tribute To Zdenko G. Fibich”) composed by John Stum:

I’m particularly fond of the performance instructions peppered throughout: Have a nice day…Add bicycle…Gradually become agitated…RELEASE THE PENGUINS…
Then we have String Quartet No. 556(b) for Strings In A Minor (Motoring Accident):

This one contains similarly entertaining directions: Players may not fly above the audience during performance…Shock therapy may be necessary to finish…With much passionfruit…
There are also such pearls of wisdom as “If arms fall off, re-attach and play much slower” and “Re-coat all of the pinatas with marmalade until most of the ox drivers have discovered the tube of antimatter won’t fit into some Barbie dolls.”
I must say, I’d be slightly frightened to step into this man’s brain.
Then we have Sylvano Bussotti’s Mobile-Stabile per Chitarre, Canto e Piano, which resembles something between a score and a mechanical blueprint.

I’m not entirely sure whether Play II for Harpsichord and Synthesizer, by John Stead is a musical score or biology textbook image:

This one would make a great poster:

World Beat Music…literally (by Wild About Music:

Holiday greeting, Stockhausen style:

Source 1
Source 2