The chanson Belle, Bonne, Sage by Baude Cordier, written in the shape of a heart, with a red note coloration string of notes forming another heart.
Most of the compositions in the Chantilly Codex date from ca. 1350-1400. There are 112 pieces total, mostly by French composers, and all of them polyphonic. The codex contains examples of many of the most popular courtly dance styles of its time, such as ballades, rondeaus, virelais, and isorhythmic motets. Some of the motets are rhythmically extremely complex, and are written in intricately exact musical notation. Two pieces by Baude Cordier were added at a slightly later date at the front of the manuscript, and use unusual shapes to reflect their musical contents. The piece “Belle, Bonne, Sage” (image right) is a play on words on the “Cor” (“heart”) in “Cordier”.
text via Wikipedia