Anne Teresa De Keersmaeker rarely makes incursions into pop culture. Excepting her recent choreography for West Side Story on Broadway, her lush mathematical dances have kept to palaces of the postmodern. But, in 2011, conspicuous chunks of two early works materialized in the Beyoncé music video “Countdown.” In the media kerfuffle that followed, the “little-known Belgian choreographer” (as one news anchor had it) quipped that schoolchildren could have done better with the purloined steps. Then, with her encouragement, they did. Children—along with hundreds of other people around the world—sent in homemade videos the length of a song. The project was called Re:Rosas!, after one of the dances that Beyoncé had admired.

On March 17, the same day that President Trump got around to admitting there was a pandemic, De Keersmaeker’s company Web site announced it was relaunching Re:Rosas! for these “times of isolation.” To participate, all you needed was a chair—plus the will to reconfigure the choreography’s mesmerizing structure and gestures for the absurd and dire situation at hand. An understated poignancy suffuses the videos.