Mariana is a beautiful painting, even if hard to penetrate for meaning at first.
Its like the Scythe in Millais' Apple Blossoms. It isn't there by accident. It has meaning, and I think its the whole reason the painting exists.
If you were to crop it out, there would be other pictorial elements that enable meaning, but we require the whole to appreciate the underlying context and intention.
Have read The City and the City by Mieville? It is a really interesting novel about observation and sub and un concious intentionality. Possibly also about the lack of free will...
My train is nearly to the city, so my free will shall be abducted shortly.
I read your review of the City and the City and I got it from the library but they wanted it back before I had read it. Right now I'm deep in psychogeography and the situationists are waiting for me, but Mieville is in my list for a future date.