Dan Flavin — American Sculptor born on April 01, 1933, died on November 29, 1996

Dan Flavin was an American minimalist artist famous for creating sculptural objects and installations from commercially available fluorescent light fixtures... (wikipedia)

A piece of wall can be visually disintegrated from the whole into a separate triangle by plunging a diagonal of light from edge to edge on the wall; that is, side to floor, for instance.
It is what it is, and it ain't nothin' else... Everything is clearly, openly, plainly delivered.
One might not think of light as a matter of fact, but I do. And it is, as I said, as plain and open and direct an art as you will ever find.
My icons do not raise up the blessed savior in elaborate cathedrals. They are constructed concentrations celebrating barren rooms. They bring a limited light.
Realizing this, I knew that the actual space of a room could be broken down and played with by planting illusions of real light (electric light) at crucial junctures in the room's composition.