Is it possible to illustrate a wave more simply and conclusively than in a mounting and receding curve? While the birds in the
sky reverse the wave-form, the real force of action is seen
developing under the water surface. There an event of dramatic
climax proceeds, causing movements which are much more dynamic
than is indicated on the surface. In the lower part of the
picture, the full purple tones portray profundity and deep
passion. Only a child or a genius would dare to unfold with
such confidence the essence of an object. The picture, which by
the way is not larger than a page of this book, was executed in
1938, two years before the artist's death, a fact which proves
that he never lost the purity and directness of his childhood
conceptions. Half a century of life and work only intensified
the clarity of his vision and his creative faculties.
(J.J. Sweeney, op.cit., p. 31)

A photo-certificate from Josef Helfenstein of the Paul Klee Stiftung dated Bern, March 15, 1990 accompanies this work.