YVARAL (1934-2002) Accelerated Structure B, 1969. Glued on white lacquered chipboard and black elastic thread. Signed, titled and dated on the back. 54 x 50.5 cm. Restorations. Collage on white lacquered chipboard and black elastic thread, signed, titled and dated on the back. 21.2 x 19.8 in. Provenance: Offered by the artist to his student and assistant. We thank Mrs. Michèle Vasarely for confirming the authenticity of this work.