import java.awt.*;
import javax.swing.*;

public class Parabola extends JApplet {
  @Override
  public void paint(Graphics g) {
    super.paint(g);
    double a = -0.0025, b = 1, c = 0;
    for (int x0 = 0; x0 < 200; x0 += 10) {
      double y0 = a * x0 * x0 + b * x0 + c;
      int x1 = x0 + 10;
      double y1 = a * x1 * x1 + b * x1 + c;
      g.drawLine(x0, (int)y0, x1, (int)y1);
      System.out.printf("(%d, %.1f) -- (%d, %.1f)", x0, y0, x1, y1);
    }
  }

  public static void main(String[] args) {
    JFrame frame = new JFrame("");
    JApplet applet = new Parabola();
    applet.setPreferredSize(new Dimension(200, 200));
    frame.add(applet);
    frame.pack();
    frame.setVisible(true);
    applet.init();
    applet.start();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}