Walter SAUER The black box Oil and coloured pencil on silver leaf Signed with initials and signed lower right "S/W/WALTER/SAUER 51.5 x 43.5 cm Provenance: Sale Brussels, Galerie Moderne, 5 April 2003, lot 362 Private collection, Brussels (acquired from the latter) To the present owner by descent Oil and coloured pencil on silver sheet ; signed with the initials and signed lower right; 20 1/4 x 17 1/8 in. Walter SAUER 51.5 x 43.5 cm