code: function rect(x, y, w, h) {
          if (!(this instanceof rect))
              return new rect(x, y, w, h);
          if (y === undefined) {
              y = x.y;
              w = x.width;
              h = x.height;
              x = x.x;        
          }
          this.x = x;
          this.y = y;
          this.width = w;
          this.height = h;
      }
docs: Rectangle. ----------