Robert Morris (artist)

Untitled (L-Beams), 1965 Three identical L shapes, each about eight feet long on a side, set in different orientations. You know they are the same shape, yet they look like three different objects. That gap between what you know and what you see is the whole lesson, and it grows as you walk around them. Morris allowed the units to be arranged differently for each space, so no two showings need look alike. The Whitney Museum of American Art owns a stainless steel version, catalogued as Untitled (3 Ls), made in 1965 and refabricated in 1970; it is not currently on view, so check before a visit. If you have time for one work on this list that explains Minimalism's interest in perception, this is it.