"Before people are even seated for “Bronx Gothic” at Danspace Project, Okwui Okpokwasili is moving. Her back to the audience, she does a shimmying, herky-jerky kind of dance. It seems like a private ritual, a gathering of forces or, maybe, a summoning of the muse. And it goes on so long, 20 minutes or so, that you worry she’ll knock herself out. Or exhaust your patience. She doesn’t. “I want to share something with you,” she says at last. It’s a story of innocence (well, relatively) and experience that grows out of a series of notes passed between two 11-year-old girls, one of whom is based on Ms. Okpokwasili, who wrote and performs this solo show."