Pethick attended the Royal College of Art in London, England, and has lived on Hornby Island for many years. His artwork explores a long-standing interest is optics, nature and alternative sciences, and 3D imaging. He often uses optical devices such as lenticular and Fresnel lenses and photographs as well as natural and man-made found objects. He has exhibited his work since 1958 and has had solo exhibitions in Vancouver, Seattle, Tokyo, Saarbrucken (Germany), Montreal, Toronto, New York and Paris among others. His work was included in the Canadian Biennial of Contemporary Art at the National Gallery in 1989 and received the DeHueck Fellowship for Arts and Science at the National Gallery in 1997 as well as a VIVA Award from the Jack and Doris Shadbolt Foundation in 2000. The Time Top, commissioned by Concord Pacific in Vancouver, is his first public art commission.