Henri Matisse. The Red Studio, 1911. Oil on canvas, 72" x 86."
This picture epitomizes the notion of the "optical space" in painting - a space with a certain kind of dimensionality which you can imagine entering and moving through, but not with your body, just your vision.
The red floor and walls, all of essentially equal value and density, bring the ground right up to the picture plane, but the diagrammatic lines and the small retrospective of Matisse's works from that time carries me around the space almost as if on a guided tour. There's a wide point of entry at the center bottom; my eye follows the edge of the table past the plant and bottle to the reclining nude, then around the room, pausing at the pictures, grandfather clock, and sculptures, finally resting in the chairs in the lower right - much like the trajectory I would probably have followed in the actual room.
Matisse had the magical ability to create a flat, patterned space in which color was the dominant aspect without ever turning to abstraction. This is a much rarer accomplishment than you might think - representation of any kind has a tendency to throw purely visual concerns into the back seat.