In 1974, Reich began writing what many would call his seminal work, Music for 18 Musicians. This piece involved many new ideas, although it also hearkened back to earlier pieces. It is based on a cycle of eleven chords introduced at the beginning (called "Pulses"), followed by a small section of music based on each chord ("Sections I-XI"), and finally a return to the original cycle ("Pulses"). This was Reich's first attempt at writing for larger ensembles. The increased number of performers resulted in more scope for psychoacoustic effects, which fascinated Reich, and he noted that he would like to "explore this idea further". Reich remarked that this one work contained more harmonic movement in the first five minutes than any other work he had written.