STOWE, Vt. — Across three adjacent screens, a warrior slathered in black oil and clothed only in dark briefs draws her double-edged sword, carefully, ceremoniously, across another combatant’s. The opponent falls back, both sword arm and sword outstretched to keep her at bay. The warrior grips her blade with her naked left hand, applies force. Her opponent sinks to her knees still holding her own sword like a talisman, like a shield, like a plea …