Left: 'Polypropylene Chair' mark II, 1964 and 'Polypropylene Armchair', 1967. Day and Hille pioneered the use of the material for seating. Courtesy of the Robin and Lucienne Day Foundation. Pictured right: Day designed signage, such as this example, for the Festival of Britain, 1951, as well as furniture. Photography: Cracknell. Courtesy of Design Research Unit