(in the corners.)
"The best part of LeWitt's art, however, isn't how it's made, it's what it does. The finest wall drawings -- and these, by and large, were designed before 1993 -- render one of art's most invisible qualities, content, visible. They make you understand architecture as material; why the wall is a subject; how image, abstraction and text connect; what logic, authorship and even capitalism look like when they're thrown into question. This is no mean feat; it's almost miraculous..."
taken from Jerry Saltz's article here...
(images from top to bottom)
1. sol lewitt: Wall Drawing #146. All two-part combinations of blue arcs from corners and sides and blue straight, not straight and broken lines., September 19722. richard wright, wall drawing
3. neil campbell : c/o marianne boesky, here 2008
4. unknown wall drawing