Here we talk about the most common single letter/Chinese character favicon. In addition to the relatively full W, dig, easy, other degrees of modification, and rounded corner box is the most common way. Like M, B, west, is similar to the Yin seal style, the advantage is that it is less than the Yang wen such as Sogou S; And it can be made straight like B, or it can be interlinked with both inside and outside like M and West.