CTR+SID (center/side) allows you to create a polygon 
entity by specifying the number of sides, rotation angle, 
side length, 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 the length of the polygon's sides and press <Enter>.

Indicate the type of polygon you want by choosing from the
following options:

OUTLINE - to assign the active entity color to the polygon
outline. This color must be set before the entity is 
created, using the SET option or the COLOR parameter in 
the Status Window.

FILLED - to automatically fill-in the polygon with a color
from the color palette supported by your graphics card.
The system sets colors 1-15 for you; colors 16-255 are set
by your card. Select from the color palette or enter the
number of the color desired and press <Enter>.
