During his long association with Knoll he designed many important pieces of furniture, including the Grasshopper lounge chair and ottoman (1946), the Womb chair and ottoman (1948), the Womb settee (1950), side and arm chairs (1948–1950), and his most famous Tulip or Pedestal group (1956), which featured side and arm chairs, dining, coffee and side tables, as well as a stool. All of these designs were highly successful except for the Grasshopper lounge chair, which, although in production through 1965, was not a big success.