The Twins double pictures are meditations on the theme of control and chance. Since it can never be completely foreseen how the distribution of the pigments will look once the twin canvases have been separated, the artist here delegates a large portion of his responsibility to the material and the process. The contact method of working also touches on conceptual issues: What is the original and what is the copy? 

Most significantly, however, the Twinsgive the viewer much to see and discover. We can distinguish between the individual layers of paint, and we can understand how through the imprinting the deeper layers of the one painting are reversed to become the upper layers of the other. In short, with the method of contact painting, an instrument rich in artistic possibilities was created, one with which the artist could experiment over a long period of time.

(From an essay by Peter Lodermeyer)