1. (While it doesn't appear that I will actually be teaching landscape painting this summer since no one has signed up - I have been preparing my class notes for it today. So... ) I was thinking about Cezanne, who developed a way of creating atmospheric depth purely by color relationships rather than gradually fading the chiaroscuro and detail (which is visually how we perceive depth).
2. Also, I was part of a really good student's senior critique this week, and she had a bunch of abstract work with some representational elements mixed in. she was playing with formal elements creating some interesting spatial relationships.
3. And I recently read again, for class, Clement Greenberg's "Modernist Painting," which argues, modernly, that optical space, rather than illusionary space, is the only space appropriate for painting.
All of these converging ideas have lead me to think, purely for fun formal play, not philosophical reasons...
It would be fun to do landscapes with the flat patterning of Japanese art, also using Cezanne's color theory - so that a fun optical depth is created, though not an illusionary spacial depth. The result would probably be a cool patteren that played tricks on your eyes.