A bowling pin is an object associated with the game of bowling. For Spacesim purposes, the shape of a bowling pin is sometimes useful for describing objects in space that are not perfect geometrical solids.
Imagine a cylinder with radius r and height h. From one end, the radius decreases slowly until the cross-sectional area of the cylinder reaches a minimum at about 2/3 h. Then the radius increases slowly and decreases again, producing a bulbous end on the shape.
Using the Shape
Using descriptions such as "Bowling Pin Shaped" is not exact in any sense of the word. However, it does give the reader a general idea of the appearance of the object. To give some scale, provide the radius r and height h, as if the bowling pin were a cylinder.
The Bowling Pin shape is used to describe comet Borrelly.