Optical Art was an abstract art movement from the 1950s to 1960s that used simple repeating shapes and colors to create confusion between the foreground and background. Key artists included Bridget Riley, Victor Vasarely, Heinz Mack, and Jesus-Rafael Soto, who experimented with optical effects in paintings like Riley's Blaze 1 and Vasarely's Etude Lineaire through the use of lines and geometric patterns that play with perception.