The oracle-bone form shows a horse in profile: head, mane streaming, four legs, tail. Three thousand years of simplification squeezed it to three strokes, but it still gallops.
马上 'immediately' is literally 'on horseback' — the fastest thing in the ancient world. 马 is also a top-ten surname (Jack Ma of Alibaba, Ma Long of table tennis). The Year of the Horse celebrates it zodiac-wide.
Mane, body, legs in three strokes — a galloping HORSE.
马马虎虎 'horse-horse tiger-tiger' means so-so/careless — from a painter who couldn't decide if he was drawing a horse or a tiger.