Blue Night, 1937
 
 "Blue Night" is one of the series of late pastel works in which Paul Klee reduced the colors to a few basic colors.
 Marianne L. Teuber suspects that the characters in the picture refer to the patterns that Max Wertheimer used in his essay "Investigations on the Study of Gestalt", published in 1923 in the journal "Psychologische Forschung", to illustrate the theories of his Gestalt psychology.
 
 Paul Klee, Blue Night, 1937
 Kunstmuseum Basel, online collection http://sammlungonline.kunstmuseumbasel.ch/eMuseumPlus 14.02.2018