pro circ,fill=fill,thick=thick

;	Defines user symbol as filled or non-filled circle.

if n_elements(fill) le 0 then fill=0
if n_elements(thick) le 0 then thick=!P.thick

N=16

a=findgen(N)*(!Pi*2/(N-1))
usersym,cos(a),sin(a),fill=fill,thick=thick
	end