Yet his messages are anything but invisible. "The main focus and theme of my creations revolves around reflecting social problems in China," Liu says.
"The main idea is to highlight and encourage reflection upon the problems our society turns a blind eye to," he explains. "As a life form, we're extremely vulnerable and susceptible to the influences of our external surroundings. The person in my work stands for someone who is helpless and alienated, someone who cannot independently construct his ideals and grasp his own destiny.
Liu concedes that at first he did not set out to become a full-time artist.
"In the beginning, I chose to study painting out of sheer enjoyment and pleasure. I was never really sure where this path would take me," he says.
In 1991, Liu was admitted into the Shandong Art Institute. "The artistic scene and atmosphere was very much alive and thriving at the time," he recalls.
"After 1989, China saw a huge influx of different ideas and revolutions, all jostling for position in the creative community. Western artistic ideals poured into the country with the ferocity of a storm. It was then that I began to familiarise myself with a completely different form of artistic expression and began to reflect upon my own position in society."
When he was 30, Liu went through a rough patch. "I had no job, no income and no dignity; there was no one to love and no one who cared," he recalls. "At 30, I had managed to lose everything. Those times made me feel like I was completely dispensable in society. It was this that directed my main artistic focus onto protesting injustices in our society."
In 2005, he had another jolt to his artistic vision. "On November 16 that year the art studio I had at the time was forcibly taken away from me by the government. In a fit of rage, I decided to speak out about and explore social problems through my creations. My art became my strongest tool to fight back."
Liu urges aspiring artists to take a stance in their art. "I tell people that 'You can live according to your ideals as long as you believe in yourself and persevere,' he says. "If you adhere to your ideals and constantly try to progress in your art, someone out there will notice your work, be moved by your spirit, and be attracted by your talent. Then it's only a matter of time before they want to buy your work."
Liu likes to use Hong Kong as a backdrop for his urban camouflage creations. "The city's unique historical trajectory makes it an ideal cultural and political [halfway house] between East and West. I will strive to incorporate those features into my pieces."
So should you spot the trace of a face camouflaged among streets as you walk down a street, you'll know it's The Invisible Man hard at work.