Sen Curran’s new Art/Song/Dance consists of 12 songs plus an overture and would work better at half that. Composer Ricky Ian Gordon, who played his own music and conducted four singers in generic musical-comedy style, channels Bernstein and Gershwin and comes up mostly with mush. The choreography ranges from homespun, square-dance-based formations to vaudeville tropes; a row of “footlights” upstage never lets us forget that this is “theater,” making it difficult to care about the dancers working so hard to entertain us. Beyond the introduction of same-sex couples, nothing special goes on; the choreography literalizes the lyrics (by such luminaries as Langston Hughes, Tina Landau, W.S. Merwin, and James Agee). The demands of modern dance differ from those of the Broadway stage, and Curran has them confused. More successful was his newest work, St. Petersburg Waltz, in which Curran channels the grandfather of Meredith Monk, who composed the score. His character study of a tart old man modulates its gestures from large to very subtle, concluding with Grandpa davening as the lights fade.