Nine

This is an artwork by Bridget Riley, a British artist known for her exploration of optical illusions and movement in art. This particular work is an example of op art, a style of art that uses optical illusions to create a sense of movement or vibration. The work is characterized by its use of simple geometric shapes and bold colors, which create a sense of depth and movement. The work is also a reflection of the artist's interest in the relationship between the viewer and the artwork, and how the viewer's perception of the work can change depending on their position and perspective.