Paul Klee was a Swiss painter and important figure in the development of early 20th-century avant-garde art. Klee’s breadth of subject matter ranged from the child-like portrait Senecio (1922), to the geometric abstraction of Castle and Sun (1928). He often painted architecture as well as the natural world, using his signature expressionist style to represent space. “Spatial art does not begin with a poetic mood or idea,” he mused. “But with construction of one or more figures, with the harmonizing of several colors and tones, or with the devaluation of spatial relationships and so on.” Born on December 18, 1879 in Münchenbuchsee, Switzerland, his imagination as well as an appreciation for art and music...