Double diamond method is the name of a design process model popularized by the British Design Council in 2005. It was adapted from the divergence-convergence model proposed in 1996 by the Hungarian-American linguist Béla H. Bánáthy. Two diamonds represent the process of wider or deeper investigation of a problem (divergent thinking) and subsequent focus of action (convergent thinking). He suggests that the design process has four phases: discover, define, develop and deliver.