His favourite scenes were of shadows, clouds, heaps, reflections, flat compositions, angular, unbalanced and obstructed views. Compositions were fields of items in tension, and the way these functioned to anchor relations of acknowledgement was something he thought he already understood. Clouds belonged in the family of saliencies which was akin to this. Shadows and reflections were different and obstructions different again. The former were a matter of the layering of one space over another, the ambiguity and mixing of separate fields, of which one was generally three-dimensional and the the other flat. This contained an allusion to the illusory qualities of depth perception. Obstructions also had a demystificatory dimension - the sudden frustration of the entitlement to transparency and depth, the something-in-the-way that blocks the spontaneity of the viewer and causes them to become aware of their seeing, the invisible functioning that embraces their entire world. This is why obstruction is best when it is blank and blind, a piece of pure texture.