These look suspiciously like Poincaré half-plane models of the hyperbolic plane (there are pieces of artwork by Escher specifically based on the hyperbolic plane).
Note that these pieces do not contain the whole half-plane, of course. But it is not too hard to imagine extending the artwork left, up, and right into the whole half-plane. The second piece would also need to be extended downwards, but since the lizards are shrinking exponentially, they would converge to a line, it appears.
My question is, as interpreted as half-plane models, would these correspond to tessellations of the hyperbolic plane? (It would also be interesting to see them changed into other models of the hyperbolic, such as the Poincaré disk model.)
(It's interesting, because if so, this presents a much easier way to replicate Escher's work. Drawing in a half-plane model appears to be much simpler than in a circle model. So the artists could draw in the half-plane model, and then use a computer to convert to the circle model.)
EDIT: For example, figure 1 of this paper shows a tessellation by square like shapes of the hyperbolic plane, displayed in the half-plane model. It looks very much like the second print.