A procedure for generating different variations of a sequence of symbols, such as a musical piece, based on the properties of a chaotic system--most notably, sensitive dependence on the initial condition--is described and demonstrated. This method preferably uses a fourth order Runge-Kutta implementation of a chaotic system. Bach's Prelude in C Major from the Well-Tempered Clavier, Book I serves as the illustrative example since it is well-known and easily accessible. Variations of the Bach can be heard that are very close to the original while others diverge further. The system is designed for composers who, having created a through-composed work or section, would like to further develop their musical material. The composer is able to interact with the system to select various versions and change them, if desired. Yet the compositional character of the variations remains within the artist's domain of style, expression and inventiveness. The procedure, however, is more generically applicable to other dynamic symbol sequences other than music as well.