Bridget Riley credits this work from 1961, Movement in Squares, as the beginning of her exploration of geometric form and spatial dynamics. Its rhythm subtly evokes a meeting of two forms, a kiss or a folding of two flat planes into a vanishing line of contact. The repeated squares, gradually compressed from left and right, give a restless impression of movement, and refuse to let the eye settle. Riley’s painting featured in the Hayward Gallery’s 2006 exhibition How to Improve the World: 60 Years of British Art, Arts Council Collection.