I suspect "fuzziness" here is something specific? E.g. fuzzy-edged shadows from the sun seems pretty obvious - it's not a point light source. So this is refer

I suspect "fuzziness" here is something specific? E.g. fuzzy-edged shadows from the sun seems pretty obvious - it's not a point light source. So this is referring to... nano-scale edge fuzziness or something? Or the shenanigans needed to do sub-wavelength features (like we do for silicon lithography)?