I know how to derive Gauss's law considering only one point charge and a sphere. I've seen other derivations for other geometrical shapes and I would say this is way too tedious as a method to prove that Gauss's law always holds true. I was wondering if there is a general proof that says this has to be the case for all charge distributions and all geometrical shapes? Namely, Θ=Q/εo holds true always. Also, I'm not looking for proofs that refer to the fact that the "irregular shape is equivalent or reducible to the spherical case". I'm considering cylinders, cubes, and other polygons which as far as I know are not reducible to the spherical case. Thanks.