Irving Harper

Marshmallow Sofa, by Irving Harper for George Nelson's studio, 1956 Eighteen round cushions fixed to a steel frame, and the most cheerful silhouette in furniture. It was long credited to George Nelson; Harper, working in Nelson's office, is now recognised as its designer. Herman Miller made only 186 in its first five-year run, and Vitra now produces it under licence. Treat it as sculpture you can sit on. The discs give decent support for perching and conversation, but there is no sinking in and no lying down, so it works best in a hallway, studio or second living room rather than as the family's only sofa. Expect a high price new and collector prices for early examples.