Burma-Shave was brushless shaving cream from the 1920s. Burma-shave advertising signs may have been early billboards. How it worked was successive signs conveyed the advertising message:
In politics, the concept has been widely used in campaigning:
Roger Miller (King of the Road), known for his country honk novelty songs, also had a silly tune about this whole business called Burma Shave. YouTube at present only has a version by the Everly Brothers:
Phil and Don have another song reviewed here, too: Man With Money.