 Head VI was the first of <unk> 's paintings to reference <unk> , whose portrait of Pope Innocent X haunted him throughout his career and inspired his series of " screaming <unk> " , a loose series of which there are around 45 surviving individual works . Head VI contains many motifs that were to reappear in <unk> 's work . The hanging object , which may be a light switch or curtain <unk> , can be found even in his late paintings . The <unk> cage is a motif that appears as late as his 1985 – 86 masterpiece , Study for a Self @-@ Portrait — <unk> . 
