||La Persistencia de la Memoria (The Persistence of Memory) takes its title from the iconic surrealist painting ("The Persistence of Memory") by Salvador Dalí. The flexibility of this work's tempo, unusual for a work in which the electronics are closely coordinated with the live performer, mirrors the flexibility of the clocks in the painting. Flamboyant electronic transformations reflect the personality of the painter, and the whimsical directions in which he later took the images presented in the original painting. The work is scored for interactive electronics and a midi-generating acoustic piano, such as a Disklavier or an acoustic piano with a Moog Music PianoBar. A MAX score-following "patch" receives midi pitch data from the piano, and controls the electronics by measuring the continuously changing tempo (as directed in the score) of the pianist's playing. The electronics consist of six rather anodyne contrapuntal tunes, in conventional styles (particularly boogy-woogy blues), which play with varying probability and degree of distortion, depending on the moment in the piece, and on whether the pianist is accelerating or decelerating the tempo of the music. The pianist plays lines taken directly from the electronics, and new unpredictable music, derived from register-specific combinations of notes that come from the different electronic lines. Because of the probabilistic nature of the interaction between the piano and the real-time electronics, the electronic music will be different each time the piece is performed, but its overall shape and character will persist across performances. Although the completed work ended up having quite a whimsical character, my original concept was the exploration of memory and its effect on our perception of the present. The electronic parts play melodies that counterpoint the pianist's music, but which, based on probabilistic algorithms, come in and out of focus, like imperfectly remembered obsessive melodies distorted by memory. As the piece progresses, the tempo becomes more and more unstable, and more and more electronic distortions and musical "non-sequiturs" are introduced. Gradually the electronics become less recognizable, becoming distorted echoes of the tunes, timed to the pianist's current tempo. The pianist finally tries to bring everything under control by reverting to mindless scale-like technical exercises, which speed up the electronics to their "breaking point," until they collapse at the end of the piece.