As massive demonstrations rock Hong Kong’s streets, protest art—not in the form of graffiti, but in the form of sticky notes—has popped up all over the city.br br The walls of Hong Kong are now hotspots for people to vent their anger against the government and offer words of encouragement.br br How did sticky notes become a dominant form of protest? And what are the demonstrations about anyway? We checked out a few of these “Lennon Walls” to find out.