anx.framework/lib/nant-0.91/examples/StyleTask/SimpleExtensionObject/SimpleExtension.cs

using System;
   
//Calculates the circumference of a circle given the radius.
public class Calculate {

   private double circ = 0;
      
   public double Circumference(double radius){
      circ = Math.PI*2*radius;
      return circ;
   }
}