In the 1960's, an artist from London named Bridget Louis Riley explored the dynamic potential of optical phenomena and developed an art movement known as "Op Art". In Riley’s paintings she depicts irregular three dimensional surfaces by using warped lines which are thinner or thicker in certain areas or arranged in particular angles and spacing to create a sense of depth and movement. Op Art pieces produce a disorienting physical effect on the eye creating an active relationship between the painting and the viewer.