Back to art history lectures at art school, the one where you were awake, and that's what this door on an old tractor reminds me of. All of the rectangles, the black lines of the seals on the windows and the hard diagonal shadows.
Magically the dirty windows have turned the sky into Norfolk Bog Door Blue as well and that is an unintentional bonus so much so that you can almost feel a work of art, a masterpiece coming together and how could I forget to mention the green mould highlighted by the clumps of moss. Of course the mould can be interpreted as delicate brushwork or simply a touch of Fungus the Bogeyman that wonderful children's book by Raymond Briggs.
I think we'll go for the latter definition.