“The idea was there were these three people,” Merce Cunningham said of his dance Cross Currents, “who often had these quite different rhythms, and then they would come together at the end of the phrase.” Cross Currents was premiered in London, on a 1964 tour that rocketed the company to fame. Here it leads a short program that includes Frederick Ashton’s ethereal masterpiece for three, Monotones II, and a commissioned work from choreographer Pam Tanowitz, who’s having a very big year. —L.J.