The Chinese government can't stop its citizens from remembering what happened 24 years ago at Tiananmen Square, but it can try its hardest to stop them from talking about it online.

Any phrases remotely related to the 1989 protests have been banned on China's micro-blogging sites including "1989," "In today," "anniversary," and, oddly enough, "big yellow duck."

Beijing's aversion to the brightly colored water fowl can be explained in a meme that's been circulating around Sina Weibo, the country's most popular social networking site, as shown here on Twitter:

Yes, China fears memes, an example of how inventive Chinese people have been about getting around government censors. The list of banned terms even includes a fictional date: May 35, which, if it existed, would happen to fall on the same day as June 4.

Even emoticons are being banned: Candles, used to signify a virtual vigil for the victims of Tiananmen, have also been removed from Sina Weibo.

The increasing number of forbidden words and symbols explains why internet users have turned to photos to voice their opinions. A photo of a praying mantis, forelegs raised before a car tire, has been making the rounds. The South China Morning Post has an impressive collection of screenshots from Sina Weibo snapped before the government took them down.

The official government stance on censorship, according to an op-ed in the state-run Global Times, is that the censorship is for people's own good:

Most Chinese are looking forward to free speech on the internet, while at the same time are expecting an orderly social environment. People already understand that free speech can not go against social order. Internet regulation is not only an embodiment of the government's will, but is also laid on the foundation of the public interest. [Global Times]

The Chinese government is also getting more clever at disguising its censorship. While banned searches used to bring up error screens and notes that results were unavailable due to "relevant laws, regulations and policies," according to The Wall Street Journal, now they are increasingly bringing up alternative, non-controversial search results. Searching for June 4 would bring up a long list of events that happened on that date — except, of course, the protests at Tiananmen Square.

It doesn't look like the cat-and-mouse game over the three T's — Taiwan, Tibet, and Tianenmen — will stop anytime soon. Until the government lets up, China's internet users will just have to make the best of a bad situation, like film director Jia Zhangke, who posted on Sina Weibo: "Don't worry about forgetfulness. At least the Sina censors remember."