 <unk> 's output is characterised by sequences of images . He told Sylvester that his imagination was stimulated by sequences and that " images breed other images in me " . His series were not always planned or painted in sequence ; sometimes paintings are grouped for convenience but vary in execution and tone . The idea for the head series came after he returned <unk> , late in 1948 , from a stay in <unk> . In the previous three years he had been unable to find a voice ; the last surviving canvas from this period is his Painting ( 1946 ) . Although he continued to paint , he was a ruthless self critic , given to <unk> <unk> with <unk> , and no works survive from between 1947 and the winter of 1948 . <unk> Erica <unk> offered <unk> the opportunity of a solo show for the opening of her new Hanover Gallery . He agreed , but had nothing in reserve to hang . In following years , <unk> became perhaps the most important of <unk> 's early champions ; she arranged this showing — his debut solo exhibition — publicised him widely and organised <unk> for international <unk> . 
