H.G. BOIS-CLAIR (c. 1650-c. 1750): Half of a double portrait of the king with his sister. See EUR11035. This demonstrates a stereoscopic technique of BOIS-CLAIR in which two pictures are each painted in alternate stripes with a grid in front so that one picture is visible from one angle and the other from the other angle. See material about lenticular and stereoscopic and parallax pictures.
