Not allowed to paint those white walls? Take a look at the magic that artist Joan Grubin can do with pinned paper and reflected color. She creates a whole lotta color that's there.... but not actually "there". wow!
This piece is a large wall installation where the diamond shapes are described by thin strips of painted paper attached to the wall. It is the fluorescent paint on the backs of the strips that reflect color onto the wall behind, giving the piece that sense of volume (breathing).
At the edges of the pattern, the diamonds become 2-D, until finally they are drawn on the wall with pencil.
The installation below is of paper circles glued together and suspended from pins on the wall.
This one is made of lines of stapled papers.... hanging from above. It too has that secret fluorescent paint behind, casting the beautiful halos of color on the wall as backdrop.
In the piece below, those soft bands of alternating color are created only by color reflecting on the wall from (the unseen) fluorescent paint on the back of the cut paper shapes (giving the illusion that the color on the front plane is shifting).