Klee explored the subject of weightlessness in paintings with a three-dimensional construction that appear to drift in space. They are based on precise constructive principles, yet are frequently irrational in their spatial logic. In »Schwebendes«, 1930, [Hovering], the corners of the overlapping four-sided figures are only partly »rational«, that is, linked by two corresponding corners. Other links are »irrational«, or randomly created. This gives an impression of a three-dimensional structure with a disturbing perspective. Its surfaces appear to belong to different spatial levels, and to change in the perception of the observer.