There is a wry sense of irony in Siu Leung-hing's artworks - mosaics created using hundreds of stamps.
Look closely at the striking portrait of Mao Zedong and you can see he is made out of stamps bearing the head of Queen Elizabeth.
Siu, a 58-year-old police clerk, has also created a cartoon image of a policeman out of some 1,000 used postage stamps depicting Chinese chess and the Hong Kong landmarks - representing the strategic task of policing the city.
Siu, who has been collecting stamps since he was a boy, began creating his mosaics after the handover in 1997 as a way of using up stamps bearing the British queen's head which were no longer valid and were not part of collectible sets.
He said: "The subject of the image is really up to and limited by the colour schemes available in my stamp collection.
"Portraits are the hardest to construct," he added. As well as Mao and the Mona Lisa, the famous names he has tackled include Sun Yat-sen, who was commemorated in stamps issued for the centennial of the 1911 revolution.
Siu, a member of the Police Philatelic Club, had thousands of postcards featuring the image printed, which he then gifted to police personnel in Hong Kong and the mainland.
He did ask one thing in return - that some copies of postmarked postcards be remitted to him.
Siu is not interested in making money from his art. He does not plan on staging any exhibitions, nor does he warm to the idea of taking private commissions.
"Exhibitions are costly and private commissions take too much time," he said.
Siu has allowed an NGO to use an image of his mosaics on postcards and he created another one in honour of a friend's retirement - it illustrated a parable and involved portraying Jesus alongside his disciples.
The tools of Siu's trade are basic: tooth picks, glue and scissors. "Patience and discipline are the most important requirements when it comes to this activity," he added.
With this in mind, he hopes to start teaching retirees about stamp collecting and making mosaics. He believes that young people would not have the degree of perseverance required for the hobby as each mosaic can take at least three months to complete.
With the Chinese opera mask, the Bank of China Tower and a panda also under his belt, Siu is now working on the 12 animal signs of the Chinese zodiac, with the goat his current subject.