If there is one object that we can consider a symbol in the field of design that is the Arco lamp designed by Achille and Pier Giacomo Castiglioni in 1962 and produced by Flos. This is said not only by the publications related to this discipline, in which it is often mentioned, and not even by the fact that it has long been part of the collection of objects at the prestigious MOMA in New York, but perhaps even more than this its constant presence in film and television. Arco acts as a testimonial not simply because she is beautiful but because she is the bearer of a precise idea of design of which she has become the symbol. An idea that, in 1970, it was Achille Castiglioni himself who made explicit in the pages of Ottagono from which our investigation begins.