A Science-Fiction Dreamscape for the Stage Arrives at BAM

“Going into outer space, with alien portals and time travel, puts you in such a disorienting place,” Silas Riener says in a terrestrial lower Manhattan coffee shop. He and Rashaun Mitchell, his co-choreographer and longtime partner, are unpacking their latest flight of fantasy, an experimental piece called Tesseract, which lands this month at the Brooklyn Academy of Music. A voyage into the unknown—by way of otherworldly dreamscapes filtered through a high-tech lens—the project is the culmination of a two-year mind meld with pioneering video artist Charles Atlas, whose roster of past collaborators includes Yvonne Rainer, Leigh Bowery, Antony and the Johnsons, and Marina Abramović.