If that is so, would it be entirely to decrease search space for layout algorithms? I believe there isn't anything in the fabrication process that couldn't model diagonals.
I could see that square packing is more simple, but by shifting elements per row I don't see why it couldn't propagate at odd angles.
Are the next generation of Cerebras chips designed by the current generation? Maybe it won't be recognizable as a particular layout but rather a chaotic but functional vibe layout.