OK, so that diagram was intended to be horizontal, not vertical. Obviously you want to minimize vertical movement as much as possible. But I see what you mean

OK, so that diagram was intended to be horizontal, not vertical. Obviously you want to minimize vertical movement as much as possible. But I see what you mean about the sides (as drawn) being parallel. And, yes, I meant isotropic, not anisotropic. Embarrassing. OK, how about this: I have an equilateral triangle, with vertices A, B, and C. I synchronize clocks four clocks at A. I send one clock to B directly, and one to C and then B. I send one clock to C directly, and one to B and then C. I do the same from points B and C. Then, I can look at the difference between clocks that came direct and clocks that came the long way. If all the differences are the same, then I can say that going A-to-B-to-C has the same effect as going A-to-C-to-B or B-to-A-to-C or any other route. Doesn't that show isotropy?