3D Primitives and Conversions - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 139

6. We apply the ARRAY command, choose the Polar option, the center of
the array is the center of the first cylinder, and define 16 items filling an
angle of 360 degrees.
7. We copy the first cylinder 12 meters along the Z direction.
8. On the back of the building, we create another cylinder with the center at
the midpoint of lower edge having a radius of 10 and a height of 30 .
9. On top of this cylinder, we create a cone with the same radius and height,
15 .