Salmovac, a fish vaccination company, used two fishes swimming around each other to create an S in the negative space.
年賀状2017 No.06: Bang! Bang! 2017
年賀状2017 No.15: Gentleman 2017 | 2017年賀状デザイン・ポストカードデザイン- INDIVIDUAL LOCKER
It can't get simpler that this: The #logo for Milk - designed by Luis Lopez Grueiro, Spain
A fairly brilliant use of negative space and a fine logo for the electric company, H Electric, designed by Dave Burdon.
42 Beautifully Designed Single Letter Logos | Online Magazine for Designers, Artists and Photographers