Twyla Tharp goes madly formal in Scarlatti, her new piece for Hubbard Street Dance Chicago. It opens with symmetrical arrangements and rather polite, courtly contemporary-dance moves set to eight Domenico Scarlatti compositions communicating different moods. Yet her 12 dancers are never faceless pawns. As Scarlatti proceeds, they come into sharp, individual focus, defined partly by each performer's unique choreography—roguish, flirtatious, grounded—and partly by the relationships that develop over the work's half-hour. It's not like all hell breaks loose. Instead, the piece mutates into a reckless, even more detailed order. The first commission Tharp has done for HSDC since 1995, Scarlatti takes the viewer on an insanely intricate, brash, highly musical, and personal adventure. Walking Mad, Johan Inger's dreamlike, often funny nonet set to Maurice Ravel's Bolero, and Nacho Duato's Arcangelo, set to music by Arcangelo Corelli and Alessandro Scarlatti, complete the program.