public class Square implements Drawable { 

    private double center_x;
    private double center_y;
    private double radius;

    Square(double x, double y, double r) {
        center_x = x;
        center_y = y;
        radius = r;
    }

    public void draw() {
        StdDraw.square(center_x, center_y, radius);
    }
}