“One of his best-known works, N:O:T:H:I:N:G, features a light bulb and a chair.” Paul Sharits remains the most structurally precise and disturbingly unknowable experimental filmmaker of the late 20th century, much written about and yet still wholly enigmatic, his work spare, blunt, baffling, often enraged, and always overwhelmingly beautiful. P. Adams Sitney long ago claimed…