CTR+RAD (center/radius) allows you to create a polygon
entity by specifying its number of sides, rotation angle,
radius, fill type, color, and center position.

Enter the desired number of sides for the polygon (up to
eight) and press <Enter>.

Enter the rotation angle (in degrees) on which the polygon
is aligned and press <Enter>, or accept the default in
parentheses by pressing <Enter>. Positive angle values
rotate the polygon's base in a counter-clockwise 
direction. 

Enter a value for the polygon's radius and press <Enter>, 
or accept the default radius in parentheses by pressing 
<Enter>.

Determine the position of the radius by choosing from the
following options:

CORNERS - to indicate that the specified radius is to be 
          measured from a vertex of the polygon.

FLAT    - to indicate that the specified radius is to be 
          inscribed within the polygon.


The center of the polygon is determined as a point
equidistant from all vertices.
