Phi is the ratio that results when a line is divided in one particular way. That ratio is sometimes called the golden ratio, the divine proportion or the signature of God because the resulting proportions are so aesthetically pleasing and show up again and again in nature.
Picture a line divided into two segments.
If the line is divided at exactly the right point according to phi, then the ratio of the longer segment to the shorter one is exactly the same as the ratio of the whole line to the longer segment. In our illustration, the proportions of the red and blue segments are exactly the same as the proportions of the whole line and the red segment.
Inscribing a square in a golden rectangle leaves another golden rectangle. Setting up quarter circles in each of the squares create very nice spiralsThe Akron Beacon Journal has an article about two designers using phi in their space planning.
Phi, they say, yields interiors that are more calming and inviting than any arrangement they could devise themselves.Interior designers study phi in their basic course work.
A good interior designer -- one who's trained in design, not just a decorator -- will incorporate phi into the proportions of a room."One of the reasons phi works...is it results in arrangements with a pleasing kind of asymmetry."
Bev & Mike
Landfair Furniture + Design Gallery
Phi Golden Ratio Interior Design Bev & Mike