The golden ratio (phi) represented as a line divided into two segments a and b, such that the entire line is to the longer a segment as the a segment is to the shorter b segment.
A golden rectangle with longer side a and shorter side b, when placed adjacent to a square with sides of length a, will produce a similargolden rectangle with longer side a + b and shorter side a.
A golden rectangle can be constructed with only straightedge and compass by this technique:
Construct a simple square
Draw a line from the midpoint of one side of the square to an opposite corner
Use that line as the radius to draw an arc that defines the height of the rectangle
