For this project I have selected Rosbuad Musica Viva 1959 by Josef Muller-Brockmann.
It is part of a series of famous posters he designed for the Zurich Tonhalle from 1950-1972. The colored squares represent the harmony of music. I believe this falls into the Pathos mode of appeal, but could also be Ethos as well.
I could also cover the series, or a few from the series as there are many.