// Drawing spirals with turtles.

import java.awt.*;       // Import Abstract Window Toolkit
import java.applet.*;    // Import Applet stuff

public class SpiralWorld extends TurtleWorld 
{
     String parameterNames [] = {"Steps", "Angle", "Length", "Increment"};
     String parameterFields [] = {"5", "144", "200", "0"};
     ParameterFrame params;

     //------------------------------------------------------------------------------
     // The following main method is needed to run the applet as an application
     public static void main (String[] args) {
       runAsApplication(new SpiralWorld(), "SpiralWorld"); 
     }
     //------------------------------------------------------------------------------
     
     public void setup() 
     {
          params = new ParameterFrame("Spiral Parameters",
                                      TurtleWorld.frameSize, 0,
                                      173, 165, 
                                      parameterNames, parameterFields);
     }
     
     public void run() 
     {
          SpiralMaker spiro = new SpiralMaker();
          spiro.spiral(params.getIntParam("Steps"), 
                       params.getIntParam("Angle"), 
                       params.getIntParam("Length"), 
                       params.getIntParam("Increment"));
     }
}

class SpiralMaker extends Turtle 
{
     public void spiral (int steps, int angle, int length, int increment) 
     {
          if (steps <= 0) {
               // Do nothing
          } else {
               fd(length);
               lt(angle);
               spiral(steps - 1, angle, length+increment, increment);
          }
     } 
}