The Tress of Wisps is a form of music used to commemorate important events originally devised by the human Aspa Sleevemists. The rules of the form are applied by composers to produce individual pieces of music which can be performed. A speaker recites any composition of The Amethyst of Watchfulness while the music is played on a stasbo. The musical voices are joined in melody. The melody has short phrases throughout the form. Only one pitch is ever played at a time. It is performed without preference for a scale and in free rhythm. Throughout, when possible, composers and performers are to play rapid runs and spread syllables over many notes.