The first one takes place when both sides of a design are the same in shape, lines, texture and so on. Because this is the way we design today, this happens most of the time along a vertical axis, so when we talk about the two sides of a design, we talk about left and right. There are also examples along the horizontal axis and sometimes even along both of them, but these are rare. The symmetrical designs are pretty much most of the websites on the internet until 5 years ago.