They didn't manually adjust the glass until it worked (which would be infeasible), they wrote a differentiable simulator and used it to determine the material to use at each point via gradient descent, which is quite a feat.
That's exactly as self-assessing and self-modifying as a neural network implemented using any other kind of computation substrate.
That's exactly as self-assessing and self-modifying as a neural network implemented using any other kind of computation substrate.