‘Orange: colour, line, tone’, (1969). Oil on canvas. 92 x 137 cm.

At art school during the 1950s we were taught the Basic Course, which involved exploring line, colour, structure and so forth separately. However, there was no guidance as to how they were to be brought together again. I must have spent more than a decade after college trying to make sense of the art education I received. In one 1969 canvas, I painted an orange - a fruit that served as an emblem of nature - three times in terms of line, tone and colour within one canvas but I left it up to viewers to bring the three images together in their minds. This was one of a large number of orange pictures executed at intervals between the 1965 and 2013.