Otl Aicher was a German graphic designer, typographer, author, and teacher.
Typography wise, he is best known for the Rotis. An extensive collection of type families each including numerous styles (including a Semi Serif- which I didn’t even realize could be a thing).
He is actually probably better known though for his designs for the 1972 summer Olympics in Munich. He used a bright color palette, the Universe typeface, and created pictograms for each of the sports played (a pretty good way to communicate to the numerous languages present at such an event).