These "Eternity" signs along the footpath in Lilyfield Rd are a good example. They cleverly invoke something unique to Sydney -- specifically the story of Arthur Stace.
He was a reformed alcoholic who converted to Christianity. As a way to express his newfound love of God he painstakingly wrote the word "Eternity" in chalk on Sydney footpaths around half a million times.
The signs railing against the WestConnex motorway project appear to have been stencilled, which is kind of cheating given Stace's original method. Still, I thought it was an evocative use of imagery sure to resonate with Sydneysiders -- older ones in particular.