/*
 * 沙丘圖案
 * 大風(fēng)不停地刮過沙漠, 形成了一圈一圈的沙丘圖紋.
 */

import java.awt.*;
import java.applet.*;
import java.awt.geom.*;


public class Sandhill extends Applet {
	private GeneralPath curve;

	public void init() {
	}
	public void paint(Graphics g) {
		Graphics2D g2D = (Graphics2D)g;
		
		setBackground(Color.blue);
		g2D.setPaint(Color.yellow);
		curve = new GeneralPath();
		
		double x,y,py;
		double a,b,c;
		for(py = 20; py <= 380; py += 3) {
			c = (py - 20) * 4 * Math.PI / 360;
			b = Math.PI * Math.cos(c);
			for(a = 0; a <= 6 * Math.PI; a += Math.PI / 7) {
				x = 600 / (6 * Math.PI) * a + 20;
				y = 10 * Math.sin(a + Math.cos(a) * Math.PI - b) * Math.cos(c) + py;
				if(a == 0) curve.moveTo((int)x,(int)y);
				else curve.lineTo((int)x,(int)y);
				g2D.draw(curve);
			}
		}
	}
}