Paul Klee was a painter from Switzerland who was part of the blau reiter movement along with Wassily Kandinsky, whose belief that art would save people from materialism is described in "der Geiste in der Junst. Klee painted many angels, especially toward the end of his life when he was afflicted with schleroderma
one of these, the new angel became famous when Walter Benjamin called it the angel of history.
In any event, life can be laborious at times, and Having a guardian angel as your friend is a supremely comforting and the Engel Lauschens was nicknamed "engelblau" or simply "blau" to indicate not only his hue but his mission to guide us to paradise "der wege ins blau."