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

public class Difficult extends Canvas{
  protected static int[] buffer;
  protected static final int width = 70;
  protected static final int height = 70;

  public Difficult() {
    setSize(700,725);
    setBackground(Color.white);
    setForeground(Color.black);
    do_spiral();
  }
    
  private void draw_line(int x, int y, int xx, int yy) {
    for(int sy = y; sy <= yy; sy++) {
      for(int sx = x; sx <= xx; sx++) {
        buffer[sy * height + sx] = 1;
      }
    }
  }

  private void do_spiral() {
    int speed = 1;
    int x = width / 2;
    int y = height / 2;
    buffer = new int[width*height];
    for(int i = 0; i < height-4; i++) {
      int dir = i % 4;
      switch(dir) {
        // up
        case 0: 
          draw_line(x, y-speed, x, y);
          y -= speed;
          break;
        // left
        case 1: 
          speed += 2;
          draw_line(x-speed, y, x, y);
          x -= speed;
          break;
        // down
        case 2: 
          draw_line(x, y, x, y+speed);
          y += speed;
          break;
        // right
        case 3: 
          speed += 2;
          draw_line(x, y, x+speed, y);
          x += speed;
          break;
      }
    }
  }

  public void paint(Graphics g) {
    for(int sy = 0; sy < height; sy++) {
      for(int sx = 0; sx < width; sx++) {
        if (buffer[sy*height+sx] == 1)
          g.fillRect(sx*10, sy*10, 10, 10);
      }
    }
  }

  public static void main(String [] args) {
    Difficult d = new Difficult();
    Difficult dtwo = new Difficult();
    JFrame f = new JFrame("Challenge #18");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setSize(700,725);
    f.add(d);
    f.setVisible(true);
  }
}