function Bob(canvas) {
    this.canvas = $(canvas);
    this.colour = new Colr();
    var w = canvas.width();
    var h = canvas.height();
    this.x = Math.random() * w;
    this.y = Math.random() * h;
}

Bob.prototype.draw = function() {};
Bob.prototype.move = function() {};
Bob.prototype.toString = function() {
  return "Bob {x: " + this.x + ", y:" + this.y + ", colour:" + this.colour.css() + "}";
}