Troika is a Russian word meaning “set of three” or a “sled pulled by three horses.” In many places in the score there are three rhythmic layers working at different speeds to create a sense of forward motion. Sometimes these layers create a sense of a headlong rush, at other points the music glides along gently. The pianist may find places in the score that evoke other aspects of a troika ride: the winter wind, snow flurries, sleigh bells, horses galloping in tandem, bumps in the path, stars, or...