 Although it matches the rocks in value and hue, its spherical shape, reinforced by its cast shadow, and the suggestion of a nipple, make the metaphor clear.Dickinson at one point had painted a seated nude at the top of the picture, and Adler identifies her as the mother from which his sister at the lower right and he himself (whom Adler identifies as the old man) were born.The identification of his brother with Beethoven (not known of by Adler) strengthens the idea.