In this paper, I discuss Paul Klee's <<Glass Facade>>(1940), his monumental work, in which the atmosphere of his latest paintings is well expressed. In so doing, the following points are examined ; (1) to analyze the changes in the form in his <<Magic Square>> as a foundation to produce this <<Facade>>, (2) to clarify as <<Facade>>'s compositions the meanings of the lines ; of the colors-chiefly the scarlet in his latest works ; and of the matiere-encaustic. Especially the lines taken notice of, <<Facade>>'s lattice is very similar to putting together the two drawings, <<Enclosure>>(1940), which has been regarded as a drawing of <<Facade>>, and <<Paddle Steamer>>(1940). Judging from the <Tambourine> motifs in the drawings at that time, I suppose <<Paddle Steamer>> is a passenger boat which carried Klee to Kairouan. By the voyage in 1914, Klee got the colors. All the other things considered, it is obvious that Klee spent a lot of time on <<Facade>>, and that <<Facade>> had the meaning too deep to fathom. In his young days, Nature gave Klee the light-colors, and he had long since created his colored works, mainly <<Magic Square>>. In the end, Klee offered <<Glass Facade>> to God as <Homage to colors>.