'A small concave mirror is mounted in line behind an iris diaphragm of adjustable size. When peering through the diaphragm, the viewer looks directly into his eye's reflection. By adjusting the aperture of the diaphragm, the viewer can limit his range of vision to see his full eye, his iris, or solely his pupil.'
(Olafur Eliasson: The Nature of Things, Miro Foundation, Barcelona Catalogue, 2008)