which is which

Jan Dibbits is associated with the land art and conceptual art movements of the 1960s and 70s and holds an international reputation. His oeuvre is primarily concerned with light, observation, perspective, and space. Using string or tape on a flat surface, Dibbets forms a square or rectangle to exploit the illusion of perspective that is created by a camera. This then creates a second illusion of the square simultaneously existing off and out of the picture plane.—Wikipedia

via but does it float