Why do some PCB layouts strictly cross on both sides?

    Why do some PCB layouts strictly cross on both sides?

    I see that some PCBs are strictly double-sided crossing. Is there any purpose for this?

    Like this picture, Top is horizontal and Button is vertical.

    For low-speed signals (except for weak signals), you can arrange as much wiring as you like, which generally has little effect, but you need to pay special attention to high-speed signals or mixed strong and weak limit numbers, crosstalk between signals, and the outside world. The influence of the signal on the interior is more important at this time, but it is not the blind pursuit of vertical and horizontal. Too many vias have a great impact on high-speed signals! Of course, there is also a possibility that there are only two layers of boards, and there are many wirings. In addition, the layout is not reasonable. If you do not use horizontal and vertical, you will not be able to lay the line.

    Circuit boards are gradually developed from single-sided boards (with copper foil on only one side of the insulating board) and double-sided boards (with copper foil on both sides of the insulating board).

    Single-panel, theoretically, there is a situation where wiring is not available.

    Double-sided panels, as long as the lines on one side of the board are horizontal and the lines on the other side are vertical, theoretically they can always be used.

    This is how digital circuits run

    The thickness of the address line, data line, and control line are the same, and it is still a plug-in device. It is judged that this circuit board is a 90's product