You may enjoy reading the fiberglass weave effect in circuit board designs [0][1]. At multi-GHz frequencies, it turns out the grid-like microscopic structure of

You may enjoy reading the fiberglass weave effect in circuit board designs [0][1]. At multi-GHz frequencies, it turns out the grid-like microscopic structure of the circuit board creates dielectric constant and impedance variations, which can cause distortion in high-speed signals such as PCI-E. The solution? Always run the signal traces at an angle, so horizontal and vertical lines that are parallel to the microscopic grid is avoided. At this point, even the direction of the traces matters, and it's not even the cutting-edge, every commercial server motherboard is designed with this effect in mind, pretty amazing, isn't it? [0] https://www.ti.com/lit/an/spraar7h/spraar7h.pdf https://www.ti.com/lit/an/spraar7h/spraar7h.pdf see page 4. [1] https://blog.lamsimenterprises.com/2011/01/08/fiber-weave-effect-timing-skew/ https://blog.lamsimenterprises.com/2011/01/08/fiber-weave-ef...