A painting by Bridget Riley, titled Cantus Firmus, 1972 to 1973.

Bridget Riley 

Cantus Firmus

, 1972-1973

Acrylic on canvas

95 x 85 inches (241.3 x 215.9 cm)

Signed and dated verso

A painting by Bridget Riley, titled Cantus Firmus, 1972 to 1973.