The texture of his (or her) coat mimics the texture of the rusted can. The shadows mimic the shape of the lizard and, as Carol said, the soft green color compliments the soft tones of the rust. More significantly, however, the rusted can mimics the texture, contours, and hues of the desert landscape so prevalent in DV and the lizard represents the life force that survives the most brutal of elements. This is so well seen, Tim, which I've come to view as so typical of your perceptive eye.
