Corner House by István Orosz
István Orosz is a Hungarian painter and graphics designer, among other things. His work is on par with (or better than) any other artist designing illusion-themed art alive today. In the example below, titled Corner House, Orosz presents two windows that appear to be on opposite sides of a building. At the same time, they also appear to be facing one another making the scene confusing and ultimately impossible.
Many of his other works also contain tricks involving perspective like the one employed above. To view more of his works, visit his website at Gallery Diabolus or his blog.