I always admired these 1970s Dutch stamps, designed by Wim Crouwel. They met the UPU regulations beautifully: clear indication of the origin country and the value. Nothing else was really needed.
Exhibition catalogue for the Stedelijk Museum Amsterdam, design: Wim Crouwel / 1966
Wim Crouwel - A Graphic Odyssey
Archive: Will van Sambeek × Der Gestaltingenieur
Wim Crouwel – A graphic odyssey
Wim Crouwel designs typeface for Holland's Fifa World Cup 2014 kit
Wim Crouwel — Tile Poster Ads by Matthew Lew, via Behance
Edgar Fernhout poster by Wim Crouwel, 1963