How did Bridget Riley create the illusion of a 3D warp in the picture plane in her painting pause?

In her painting "Pause," Bridget Riley creates the illusion of a 3D warp through the use of intricate patterns and optical effects. By employing contrasting colors and dynamic shapes, she manipulates visual perception, leading the viewer’s eye to perceive depth and movement. The rhythmic arrangement of lines and forms gives the surface a sense of undulation, making the flat canvas appear to bulge or recede. This interplay of color and geometry engages viewers, inviting them to experience the painting in a fluctuating manner.