Arp declared nature to be “the measure of all things.” Metamorphosis, the constant transformation of forms, became his most fundamental artistic principle. The sense of an inherent mutability is palpably present in his sculptures from 1930 on, in which he ran through the principles he had tried out in his reliefs.
He also dealt with the multiperspectivality and changeability of form in his poetry, which was intimately intertwined with this visual art. As he once observed: “The leaf changes into a torso. The torso changes into a vase.”