In conjunction with the current exhibition “Impossible Music,” Tufts University Art Galleries is presenting a series of four player piano sessions featuring the boundary-defying work of composer Conlon Nancarrow. Nancarrow was one of the first composers to work with “auto-playing” musical instruments, particularly the player piano, because of its ability to perform scores that exceeded human ability. Nancarrow’s early work was characterized by its extreme technical demands, only rarely performed to his satisfaction. He turned to machines as a means to faithfully hear his compositions, which are complex arrangements of tempo, rhythm, and pitch. The program, which features four compositions from “Study for Piano,” will be presented again on February 14, March 14, and April 4, all Fridays.