function Square(width, height){
   if (width){
      this.width = width;
      if (height){
	 this.height = height;
      }
   } 
   
}
Create a new Square instance.
@class A Square is a subclass of {@link Rectangle}
@param {int} width The optional width for this Rectangle
@param {int} height The optional height for this Rectangle
@augments Rectangle