This feature is made of a regular polygon enclosed single entity.
1. Click on the menu bar, the "Drawing -> regular polygon."
2. Click the Drawing toolbar "draw a regular polygon command" button 
.
3. Polygon input on the command line, and press Enter.
After the execution command, the command line displays the following information:
Command: Mx_Polygon
Input side number <8>: 5
Specified regular polygonal central point or [edges (E)]:
[Circle connected to the (I) / circumscribed circle (C)] <exo>: c
Specified circle radius: 5
Polygon: a plurality (M) / width (W) / <Edges> <Current>: Enter an option or press ENTER.
Specifies the number of sides of a regular polygon. The number of edges in the range of all integers between 3-1024.
Specified regular polygonal central point or [edges (E)]: specify a point, or input e.
Center of a regular polygon: Specifies the center point of the regular polygon regular polygon drawing object.
Enter an option [a circle connected to the (I) / circumscribed circle (C)] <I>: Enter i or c or press ENTER.
Inscribed in the circle: the specified radius of the circumscribed circle, all the vertices of the regular polygon are on this circumference.
Specify radius circle: Specify a point or input values: the radius designated with a pointing device, and determines the size of a regular polygon rotation angle, a specified radius will capture the current rotational angle of a regular polygon drawn base.
Circumscribed circle: Specifies the distance from the center point of a regular polygon the center of each side.
Specify radius circle: a specified distance, the specified radius with a pointing device, and determines the rotation angle of the regular polygon size. Given radius will capture the current rotational angle of a regular polygon drawn base.
Polyline width <current>: Specifies the width, or the input value, or directly press ENTER current width.