Laurie Anderson at BAM: Songs, A Scream, Tai Chi
 Laurie Anderson launched the Brooklyn Academy of Music's fortieth annual Next Wave Festival Tuesday night with "Let X = X," an unconventional concert that featured, yes, songs from throughout her four decade recording career, accompanied by the 25-year-old avant-garde jazz band Sexmob, but also  a scream, in homage to Yoko Ono, and Tai Chi, in homage...