Inscr. lower left: Saturday Nov. 11, 1972 T. LUX F.
TLF: "I dealt with constructive (viz. geometrical) studies particularly during the first years of my teaching (1950-1955 circa) and if I have been convincing, one owes this to geometrical reseach. [...] The three studies were made, together with many others, as 'after dinner sketches' in September 1972, aiming to jumpstart my teaching mood after the free life of a nice summer..." * [304, to G. Gruber, 22.01.1991]