gistfile1.js

function Rectangle(w,h) {
    this.width = w;
    this.height = h;
}
Rectangle.prototype.area = function() { 
    return this.width * this.height;
};

PositionedRectangle = function(w,h,x,y) {
    Rectangle.call(this, w, h);
    this.x = x;
    this.y = y;
};
PositionedRectangle.prototype = heir(Rectangle.prototype);
PositionedRectangle.prototype.constructor = Rectangle;

ColoredPositionedRectangle = function(w,h,x,y, clr) {
    PositionedRectangle.call(this, w,h,x,y);
    this.color = clr;
}
ColoredPositionedRectangle.prototype = heir(PositionedRectangle.prototype);
ColoredPositionedRectangle.prototype.constructor = PositionedRectangle;