Donovan B. answered 12/09/19
Your mind can achieve great things!
From about 1890 to 1939, Pleyel (the French company that made the "double piano") manufactured and produced less than one-hundred double pianos called Duo-Claves. Stravinsky had Pleyel make him one while working on the "Concerto for Two Pianos" in 1935. That specific piece, he showed off the piano with his son, Soulima, although he had it made for Craft and himself. Igor was romantically in-love with Robert and wanted to use the Duo-Clave as a way to get closer with one another. Craft didn't reciprocate the same feelings, in fact, he had later even told of Stravinsky's gay affairs during his marriage with his wife, and how he admitted loving Craft who was indeed 40 years younger than himself. He died of heart failure just a few years later.