In 1960 the artist developed the use of collage with gouache as a quicker method of working. The most important of the early collages is 'Mandala' 1962. There are examples here from most periods but some of the most powerful are later works such as 'Chain Reaction' and 'Danger Point' in 1996 and 'Rainbow Figure 1' and 'Rainbow Figure 2' in 2000.