Final answer:
A strong example of outsider art is William Garnett’s 'A Smoke Backstage.' It embodies a unique and unconventional style, challenging societal norms.
Step-by-step explanation:
A strong example of outsider art is William Garnett’s 'A Smoke Backstage.' Outsider art refers to artwork created by self-taught or non-professional artists who are outside of the mainstream art scene. It often embodies a unique and unconventional style that is unconstrained by traditional artistic techniques or ideas. 'A Smoke Backstage' exemplifies this with its raw and expressive qualities, offering a fresh perspective on art and challenging societal norms.