In honor of Pi Day, here's a mathematical query related to phi: What shape's surface area, when divided by the area of a square of its same dimensions, equals the golden ratio? 

The DOR (direct opposite reverse), of course! 

Caffe Destino has just opened an exhibit dedicated to the shape, which Portlander David Sterner discovered over thirty years ago while slicing old skylight glass to make an aquarium. 

Sterner considers his accidental discovery in the late ‘70s to be the first addition to the Euclidian forms (sphere, cone, cylinder, pyramid and cube) since 212 BC. It resembles a slightly battered tin can. From some sides it’s square; from others circular. 

“I just had all this stuff in my living room and thought it should be out where people can see it,” says Sterner of the display at Destino; he hadn’t mounted an exhibit in 6 years. 

Seven interactive displays include lasers, 3D glasses and TV clips from the ‘80s. Visitors can even cut and paste their very own DOR while sipping coffee at an origami-esque station. Pop on a pair of headsets to learn how the shape refracts laser beams in a figure eight and why the DOR lens photos look so surreal and vaguely 3-D, like an acid trip captured on vintage film. 

“I’m hoping visitors, when they can actually touch the stuff, can understand by osmosis,” Sterner says. 

We feel more like Einstein already, but maybe that’s the espresso talking. 

SEE IT: The DOR Exhibit is at Caffe Destino, 1339 NE Fremont St., 284-9455. Through March 31.