As they gathered inside a Hong Kong shopping mall this week, a small group of protesters silently held up blank sheets of paper as a way to express their fears that the city's culture of rowdy and colourful dissent is in peril.
Not much later, riot police entered and declared the gathering illegal. They later held up new signs of their own, a purple coloured placard warning the protesters they could be breaking a new national security law.
Eight people were detained for unlawful assembly or for obstructing officers, police said, the latest of more than 9,000 people arrested in little over a year of often violent protests.
Since Beijing imposed the new security law on Hong Kong last week, however, even peaceful protests have become risky.
People are scrubbing their online histories of sensitive content, while businesses have removed pro-democracy displays from their premises.
At the occasional flash mob rallies taking place, sheets of blank paper have become the latest protest symbol.
A 16-year-old named Jessie, among around 70 people gathered at Kwun Tong mall on Monday, told AFP the blank sheets were a message for the government.
"What you cannot see is what we cherish most, and what you cannot see will continue to exist in our hearts and minds," she said.
"Maybe at this point our freedom of speech is undermined, but after the past year I am sure people's minds are not blank."
- 'White terror' -
Over the last year protesters have waved flags and banners emblazoned with slogans or chanted rallying cries that are now illegal under the new legislation.
Monday's protest was noticeably quieter.
"This piece of white paper represents white terror," said 17-year-old student Carrie, using a Chinese term for political persecution.
Over the last few days the Hong Kong government has pulled politically sensitive books from public libraries -- ostensibly to evaluate the legality of their content.
One book was by activist Joshua Wong, whose activist group Demosisto announced it was disbanding after the law passed.
Despite the fear and uncertainty surrounding the new laws, traditionally outspoken Hong Kongers are finding creative new ways to voice dissent -- including using oblique wordplay that is a feature of Cantonese.
The most popular rallying cry of the pro-democracy movement -- "Liberate Hong Kong... Revolution of our time" -- has been declared illegal by authorities for pushing secession, so protesters have turned to chanting phrases that sound similar, but with a different meaning.
One 54-year-old, who gave his surname as Law, said the government could end up in a game of linguistic cat-and-mouse with opponents.
"If the government were to release a blacklist of words, I am afraid it would have to update the list every day," he told AFP.
"If you say the white papers are unlawful too then I will come out with papers in other colours," he added.