I'm curious how difficult this would be to implement. If the dynamic lighting is being accomplished with some third-party raytracing library or similar, I doubt it would be an option in the library, so it wouldn't be possible. If it's custom-made, this would require a little bit of mental gymnastics in the DL code, as the square isn't generally "normal" for this sort of thing. Things such as Point-Line distance and Line-Line intersection doesn't by default take square "radius" into account, so the equations would need tweaking. It would probably be best to match the lighting radius setting with the distance setting already existing on the pages. My brain is hurting a bit trying to consider the math of square-vs-circle light radius on a per-token basis, and as demonstrated by the page settings, there's more than one way to calculate radius; circle and square are only two.
