The Zebra Playhouse by Beck Group was designed for the Giving Gala 2011 in Dallas. I think this playhouse falls into the art category with ease. It's form is very sculptural, and graphically it could even be considered Op Art.
Shamelessly straight from Wikipdia:
Op art, also known as optical art, is a style of visual art that makes use of optical illusions. "Optical art is a method of painting concerning the interaction between illusion and picture plane, between understanding and seeing." Op art works are abstract, with many of the better known pieces made in only black and white. When the viewer looks at them, the impression is given of movement, hidden images, flashing and vibration, patterns, or alternatively, of swelling or warping.
So how did they build that? The playhouse is constructed from plywood and 4" insulation foam pieces cut by CNC (computer numerical control) machines. If that's not enough of an explanation this promotional video may help.
I can only imagine the thought and time that went into the design and construction!
Now that's one way to do it! It's always fun to see how these structures are moved.
I stumbled upon this one at design boom, but Op-art also has a write up.