He studied cubism, surrealism and was introduced to new American art by his wife the sculptor Flora Macdonald. He moved towards abstraction, attempting to utilise aspects of landscape, poetry and Celtic art. His most significant work, A Point in Time (1929–38), has been described by art historian Duncan Macmillan as "one of the most important Scottish pictures of the century and one of the most remarkable pictures by any British painter in the period".[20][16][21]