.box {

  width: 400px;

  height: 400px;

  background-color: green;

  background-repeat: no-repeat;

  background-image: url(http://placehold.it/200/f00&text=bottom_right),

url(http://placehold.it/150/0f0&text=bottom_left),

url(http://placehold.it/150/00f&text=push_from_bottom);

  background-position:

    bottom 1em right 2px,

    bottom left,

    left 50% bottom 90%

}