POLYGON allows you to create a polygon. After you pick the
eighth vertex, the polygon is automatically closed.

Create a polygon by choosing from the following options:

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

CTR+SID -  to create a polygon entity by specifying the
number of sides, rotation angle, side length, fill type,
color, and center position.

RECTANG - to create a rectangular polygon entity (four
sides) by indicating positions for opposite corners, or 
by specifying the rectangle width, height, fill type, 
and lower left corner position.

STRING - to create a polygon entity by selecting planar
positions and stringing the vertices of the polygon to the
desired shape.

MESH - to generate a polygon mesh that approximates a 
two-curve, three-curve, or four-curve swept surface, a
tabulated cylinder, a ruled surface, a surface of
revolution, or a sphere. It is also possible to change the
direction (normals) of a grouped polygon's mesh.

A polygon is made up of one complete entity and must be
manipulated as a whole. If you want to edit parts of a
polygon, use the LINE, N-GON options to create the polygon
out of separate line entities. You can then manipulate 
each side of the polygon as a separate line entity.
