Where the shape comes from
A horse standing in profile: the mane bristling along the top, the body and head to the left, the four legs written as the four dots underneath. The simplified 马 keeps the outline in three strokes and drops the legs. It marks horses and riding — 骑, 驾, 驶 — and it lends its sound to a whole family of everyday characters: 妈, 吗, 码, 骂.