// SquareWorld.java
// Use a turtle to draw a "staircase" of squares

import java.awt.Color;

public class SquareWorld extends TurtleWorld { // SquareWorld is a subclass of TurtleWorld
  
  // define class constant(s)
  private static final double START_LENGTH = 150;
  private static final int START_LEVELS = 4;
  private static final double SHRINK_FACTOR = 0.5; // specifies the next box's relative side
                                                   // length; e.g., if the current side length 
                                                   // is 80, then the next side length is 40
  private static final Color START_COLOR = Color.BLUE;
  
  // declare instance variable(s)
  private SquareTurtle tammy;  // we'll call our turtle "tammy"
  
  // define constructor method to initialize instance variable(s)
  public SquareWorld () {
    tammy = new SquareTurtle();

    // move towards top left
    tammy.penUp();
    tammy.backward(100); tammy.left(90); tammy.forward(100); tammy.right(90);
    tammy.penDown();
    
    // set color
    tammy.setColor(START_COLOR);
  }
    
  // define the behavior when the "run" button is clicked
  public void run() {
    // draw the staircase
    tammy.drawStaircase(START_LENGTH, START_LEVELS, SHRINK_FACTOR);
  }
  
  // create a new SquareWorld
  // (this puts a graphics window on the screen
  //  and invokes the SquareWorld constructor method)
  public static void main(String[] args) {
    new SquareWorld();
  }

}