We've previously featured the optical illusions of artist Leando Erlich. One that we've missed is this installation at the 21st Century Museum of Contemporary Art in Kanazawa, Japan. It looks like a swimming pool, but is actually two sheets of acrylic with a few inches of water between them. Visitors to the exhibit at the lower level appear to be walking around at the bottom of a swimming pool. More pictures at the link.
Link via DudeCraft | Artist Website | Museum Website