21. Ninaber/Peters/Krouwel Royal PTT Nederland Mail Box, 1986 (1986) Plastic, steel Manufactured by KPN Kunst & Vormgeving, Den Haag Lent by KPN Kunst & Vormgeving 62 1/4 x 27 1/4 x 27 1/4" (158 x 69 x 69 cm) Photo by Henk de Roij, courtesy KPN Kunst & Vormgeving This very simple and functional design has become a ubiquitous element of the Dutch landscape.