The precursors of true sportswear emerged in New York before the Second World War.[2] 1930s designers such as Clare Potter and Claire McCardell were among the first American designers to gain name recognition through their innovative clothing designs, which Richard Martin described as demonstrating "problem-solving ingenuity and realistic lifestyle applications".[6] Garments were designed to be easy-to-wear and comfortable, using practical fabrics such as denim, cotton, and jersey. McCardell in particular has been described as America's greatest sportswear designer.[11] Her simple, practical clothes suited the relaxed American dress code, neither formal nor informal, that became established during the 1930s and 1940s.[2] One of McCardell's key designs was the Popover dress, which was versatile enough to work in multiple contexts from swimsuit cover-up to party dress.[12] Other McCardell signatures included ballet slippers as everyday footwear and functional pockets in skirts and trousers.[13] McCardell once proclaimed: "I belong to a mass production country where any of us, all of us, deserve the right to good fashion."[14][15] Other sportswear designs often used elements of sporty informal or casual wear such as Clare Potter's innovative evening sweater and evening skirt draped like a sidesaddle riding habit.[16]