The Italian designer and architect Pier Giacomo Castiglioni, the second of the three Castiglioni brothers, took his diploma in architecture at Milan Polytechnic in 1937. In 1938 Pier Giacomo Castiglioni and his elder brother Livio founded a practice in Milan, which the youngest Castiglioni brother, Achille, would join in 1944. In 1952 Livio left the joint practice to go his own way. Achille and Pier Giacomo Castiglioni continued to run the practice, collaborating closely on numerous famous designer objects until Pier Giacomo died in 1968. In 1957 they presented their readymade designs: "Mezzadro", a stool consisting of a tractor seat mounted on a substructure, and "Sella", a stool featuring a bicycle seat for a person to sit on while telephoning. These chairs would not be produced until years later, by Zanotta. Achille and Pier Giacomo Castiglioni playfully explored new design possibilities. Their designs link technological innovation, occasionally defamiliarization, and Minimalism in objects that are as aesthetically pleasing as they are functional. The two brothers were particularly successful with the many lamps they designed for Arredoluce, Flos, and Artemide. "Luminator", a Castiglioni floor lamp for Arredoluce dates from 1955; the Castiglionis designed the hanging lamp "Taraxacum" for Flos in 1960 and another hanging lamp, "Splügen Bräu", in 1961. Another Castiglioni lamp designed for Flos was "Arco" (1962), a floor lamp unconventionally structured with a long arc, lamp, and stand to resemble the features of a hanging lamp. From 1946 until his death, Pier Giacomo Castiglioni taught design at Milan Polytechnic. Numerous works by Achille and Pier Giacomo Castiglioni are in the collection of the Museum of Modern Art in New York.