When I was in high-school, my teacher suggested a very interesting method for generating some interesting Escher's like pictures. I think it is useful for you.
Get a mirror(or something like mirror) and construct some geometrical shape with this mirror, for example an cylinder, that the inner surface of this shape is mirror. Now, collect some isomorphic shape, for example shell, flower, or simply some triangles. If we put these objects inside the cylinder, we find very beautiful Escher-like shape on the mirror. With some simple method in photography, we can obtain the picture that is inside the cylinder. We can change the shape of mirror and create some elegant symmetry.
I didn't see this method anywhere. I hope it will be useful for you.
To memory of Escher.
