JavaScript question

[PrakharPaw]

I'm going through the HTML game module, and I found 

" var myleft = this.x;
    var myright = this.x + (this.width);
    var mytop = this.y;
    var mybottom = this.y + (this.height);   "

In https://www.w3schools.com/graphics/game_obstacles.asp

Can someone please explain what points are myleft, myrightm mytop and mybottom on the component? I'm confused because aren't myleft and mytop the same point on the component?

 

Please help.

Thanks,

Prakhar