Amid all the tear gas and transport chaos, there is another dimension of Hong Kong's ongoing political crisis that has gone relatively unnoticed – the proliferation of graffiti and posters put up by activists around the city. On a recent trip to Hong Kong, I was amazed to see subversive messages spray-painted across much of Admiralty and Kowloon, a situation that would be almost unthinkable in the downtown of any mainland Chinese metropolis. And even in the diverse, relatively free society that is Hong Kong, graffiti has until quite recently been a fairly unfamiliar sight. So what are these messages, and why are they significant?
Firstly, the rise of spray-painted slogans highlights that something is really wrong in Hong Kong. For people to resort to using a previously rare form of expression reflects the sense of desperation and anger they must feel amid a failure of political representation and threats to judicial independence. Publicly posting messages serves as a way for Hong Kongers to continue exercising civil liberties of expression and assembly, even after conventional channels such as striking and social media posting appear to have been encroached upon (not least for staff of Cathay Pacific).
Secondly, graffiti and posters serve not just as an alternative outlet for disgruntled, disenfranchised citizens, but as another weapon to use against a perceived hostile force. Because aside from street fights fought between radical protesters and riot police, another contest has been taking place – a battle for control of the message. Perhaps surprisingly in today's digital age, it is a battle that has moved away from the virtual spaces of the Internet back towards the physical spaces of Hong Kong's urban jungle. Primitive media forms such as graffiti may not spread as far or as quickly as digital content, but they are effective in other ways, and can be difficult to censor.
Here, I share some of the graffiti and other public notices that I observed first hand in Hong Kong. While not attempting to provide a comprehensive review, these images nevertheless offer a snapshot of the main themes being disseminated by activists on the front lines. Understanding those messages and their target audiences may be key to understanding and dealing with the next phase of this unfolding political contest.
Freedom and Democracy
This is one of the main themes seen in messages spray-painted around Hong Kong. It gets to the heart of protesters' pursuit of liberal democratic ideals, and reflects their concerns over the extradition bill which first sparked the unrest, seen by many as a sign that the city's hitherto, relatively high level of autonomy is rapidly deteriorating.
"光復香港，時代革命" (Liberate Hong Kong, the Revolution of Our Times)
More than any other phrase, this has been the rallying cry of Hong Kong protesters this summer, whether chanted at marches or written on placards. It was first conceived as a localist election slogan in 2016 by jailed activist Edward Leung Tin-kei. Despite its success in unifying protesters, it has also been quoted by the Hong Kong and Beijing authorities to argue that the protests are a challenge to Chinese sovereignty.
"Free HK" / "Keep Hong Kong Free"
"We Want Democracy"
The use of foreign flags including the American stars and stripes, British Union Jack and Hong Kong colonial flag has been a prominent feature of the protests. They seem to seek solidarity from the people of those countries while conveying an association with the supposed liberal democratic values of their political systems. While this may succeed at drawing international attention and sympathy, it also boosts one of Beijing's main narratives, that the protests are the result of "foreign forces" (境外势力 jingwai shili).
Oppression and Authoritarianism
This neologism has seen increasing use both online and offline, together with symbols that creatively fuse together the Chinese flag or Communist hammer and sickle with the Nazi swastika. The message is clear and especially poignant at a time when over a million Chinese citizens of Muslim Uighur heritage are believed to be imprisoned in detention camps. Hong Kongers do not want to suffer the same fate, and this short but powerful word is a way to raise awareness of the darker sides of China's authoritarian governance practices. As Victor Mair notes in his recent blog post, "The power of words and images, especially those that are newly created, can scarcely be overestimated."
This idea has been used to reflect a general climate of fear perceived by protesters, especially regarding companies like Cathay Pacific, where employees have been told to inform on those sympathetic to the protests. These references to Nazism and soviet-style white terror are clever, familiar associations that will chime with many of the protesters' key communication targets, whether at home, in China, or internationally.
Digs and Dogs
One of the most common characters seen sprayed around Hong Kong is this character for dog. It is a short but powerful dig at the city's security forces and political leaders, suggesting they have become nothing but loyal pets to the central government in Beijing. It highlights how much the reputation of the Hong Kong police has deteriorated among locals, having once been considered "Asia's finest". 
"黑警" (Corrupt police)
"黨鐡" ( dǎngtiě, Party Railway) a pun on 港鐡 (Gǎng tiě , Mass Transit Railway)
Aside from the city's security forces, MTR (the company which controls Hong Kong's transportation network) has emerged as another enemy for protesters, accused of siding with the police and government authorities. This has prompted frequent attempts to disrupt transport services, calls to boycott the MTR, and verbal attacks on the company.
Threats and Demands
"If we burn, you'll burn with us"
This message appears to target the police force and political leaders. Protesters seek to remind officers that they too are Hong Kongers and vulnerable to increasing encroachment by Beijing. It shows how radical some protesters have become, reportedly even carrying a copy of their will while taking part in demonstrations.
"Why threaten us with death, when we do not fear death?"
As with some of the other messages mentioned above, this phrase has been cited by the Hong Kong and mainland authorities to delegitimise protesters, accusing them of extremist tendencies and potentially allowing harsh anti-terror laws to be used.
"五大訴求，缺一不可" (Five Demands, Not One Less)
The aims of the broad constituency of protesters have been summed up in the "Five Demands". Afters months of no response, one of these demands has now been met by Chief Executive Carrie Lam, that of formally withdrawing the extradition bill.
I saw very few cases of pro-Beijing messages being displayed, and none involving the kinds of graffiti or small, scrappy posters seen above. But there were a few instances of note, including:
"70th Anniversary of the People's Republic of China"
Incidentally, it has now been revealed from Carrie Lam's leaked remarks that Hong Kong will only have a subdued celebration of the PRC's 70th anniversary next month.
"Greater Bay Area"
This phrase refers to a plan by Beijing to integrate Hong Kong and mainland Chinese cities in the Pearl River Delta. It is seen as a key way of improving the economic prospects of young Hong Kongers and in turn generating greater positive sentiment towards mainland China and the central government in Beijing.
China and Hong Kong flags
In an age when all attention is on digital, internet-based forms of communication, Hong Kong activists have turned to primitive, low-tech methods for delivering their messages. But sometimes it's the old ways that work best. For unlike in mainland China, Hong Kong's public spaces are not covered in government propaganda materials, leaving them largely empty and vulnerable to subversive slogans.
The texts and images I saw sprayed and posted around Central and Kowloon reveal a lot about the concerns of protesters and the wider citizenry. They also demonstrate, quite emphatically, that after 22 years of "One Country, Two Systems", Beijing has failed to win the hearts and minds of many in mainstream Hong Kong society. As the protests continue, so too does the proliferation of subversive, spray-painted slogans that simply cannot be cleaned up quickly enough by the city authorities.
Put simply, Hong Kong's protesters appear to be well ahead in the battle to control the message in the city's public spaces. But if there is one thing the Communist Party has proved adept at in governing mainland China over the past 70 years, it is controlling and moulding messages to its advantage. Whether they can repeat that feat in Hong Kong over the coming years and decades remains to be seen. For now, there is only one thing to do – watch this space.
 See this SCMP article on why graffiti had never previously taken off in Hong Kong.