I have no idea what to call this, and have no idea if it’s known already or not. I started fiddling around with square tilings like the ones I did a few years ago on this page This is the first one I’ve found of this type, that tiles the whole plane with no gaps.
It has perfect reflective symmetry across the line (the diagonal line through the centre, sloping down to the right at 45). And that line passes through exactly one of each different-sized square, which is neat.
It seems there is an infinite family of these; learn how to construct them here.