“I don’t begin with the appearance of form and colour as such, but with their spatial properties. That is the first step, and through building a coherent spatial order various and diverse sensations emerge. I try to sort these out and to assign them in their rightful places… If this ‘placing’ goes well the actual sensation becomes part of the formative fabric of the [work]. But until the whole is brought together, everything is uncertain and subject to change” (Bridget Riley cited in: Exh. Cat., London, Tate Modern, Bridget Riley, 2003, p. 25).