I have loved this Darius Milhaud piece for years and years, and finally last night I got to play it in a concert. What a treat to sit in the viola section and be right smack in the middle of the bitonality! And I made a good joke, which, in the spirit of the piece I will share here. The güiro is probably the most important instrument in the piece because it is what everyone else in the orchestra relies on to snap into the quick "ritornello" that separates all the languid bitonal and tritonal episodes. I spontaneously told the güiro player that he was a "güiro-hero" because he kept us all in line.
Here is an excerpt from the piece made into a highly amusing (and rather lewd at times) film by director Adrian Marthaler and the Radio Symphony Orchestra Berlin conducted by Matthias Bamert. I would love it if someone were to make a film (even an animation) of the original concept of the work as a Chaplin-like silent film with music.