For the most part, commuting to work is no fun. But for a few thousand lucky Boston commuters, their drive is slightly brightened – or for those interested in copyright reform, darkened – with the world’s largest piece of copyrighted artwork.

In 1971, former nun and artist Corita Kent was commissioned by then-Boston Gas Company president Eli Goldstone to paint the Rainbow Swash design on one of two adjacent tanks facing Boston’s Southeast Expressway. However, Kent’s original 8-inch model design would require the help of 20 other painters to reproduce the work on the 140-foot (43 m) tall tank.

Since its creation, there has been controversy over the possible sentiments of the painting. Kent was a known Vietnam War protester – like almost every other artist of her generation – causing some to speculate that a profile of Vietnamese Leader Ho Chi Minh is featured in the blue stripe of the painting. However Kent denied embedding such a profile, and in 1992 the original tank was destroyed and the Rainbow Swash was recreated on the adjacent tank, with a less-pronounced blue stripe.