// Butterfly.java
// Robert Sedgewick and Kevin Wayne
// Slightly reformatted by Andrew Davison, Nov. 2022

// https://introcs.cs.princeton.edu/java/15inout/Butterfly.java.html

/* Plots a butterfly-like curve.
 
   Reference: A. K. Dewdney's "The Magic Machine", Credited to
   Temple H. Fay of the University of Southern Mississippi.

   Usage:
     > compile Butterfly.java
     > run Butterfly
*/

public class Butterfly
{

  public static void main(String[] args)
  {
    StdDraw.setXscale(-4, 4);
    StdDraw.setYscale(-4, 4);
    double x0 = 0, y0 = 0;
    for (double theta = 0.0; theta < 72; theta += 0.01) {
      double r = Math.exp(Math.cos(theta)) - 2*Math.cos(4*theta) + 
                 Math.pow(Math.sin(theta/12),5);
      double x1 = r * Math.cos(theta);
      double y1 = r * Math.sin(theta);
      StdDraw.line(x0, y0, x1, y1);
      x0 = x1;
      y0 = y1;
    }
    System.out.println("Drawing finished");
  } /* main */


}