By Emma Griffiths
BBC News website, London
Mr Hwang averages about 50 new designs a year
Amid the lava lamps at plush new offices in central London, students are jostling to meet an elusive graphic artist, whose work is viewed by millions every day.
Dennis Hwang is known for his quirky interpretations of the Google logo, used on its homepage to reflect events from Leonardo da Vinci's birthday to the Transit of Venus.
At the opening of the internet search giant's new UK headquarters in Victoria, its doodler-in-chief is undoubtedly the star draw.
Pursued for signed prints of his designs, the 27-year-old tries to oblige everyone, and is surprisingly humble for someone whose work is seen by countless web users across the world.
"I try not to think about it, I've been told it's in the millions," says Mr Hwang, who busies himself with his day job as webmaster, running the technical side of the Google site.
"I do a lot of programming, I didn't expect to use the art side of things for a living," he smiles.
"It's worked out quite well. I get to programme by day and draw by night."
The first logo, a Burning Man stick figure - was put up when internet giant Google was still just a two-man band.
Christopher wanted to bring Roald Dahl back into the public eye
Founders Larry Page and Sergey Brin, wanted to alert users that they were taking a few days off to go to the festival in Nevada's Black Rock Desert.
These days the doodles are almost exclusively the work of US-born Mr Hwang, who has averaged about 50 a year since 2000.
During the Olympics he was creating a new design a day for two weeks. Sometimes he gets weeks of warning, other times, as in the case of the Mars Rover design, he gets hours.
Others most will never see, for example the "country-specific" logos like those for Persian New Year and Swiss National Day, which also require days of research from the designer.
And it is a difficult job trying to please a worldwide audience.
When he first started doodling in 2000, Mr Hwang's autumn-themed logo with Thanksgiving turkey, prompted an email from an Australian enjoying a mild spring, telling him not to be "so northern hemisphere".
Others prove particularly troublesome. His double helix design to mark the DNA anniversary was initially rejected for looking more like "two fishes kissing".
When it finally went up, the complaints flooded in.
"I started getting emails from geneticists and world-renowned scholars pointing out that my DNA was flawed and it wasn't a double helix - it was just two parallel strands."
Mr Hwang created this London-inspired design for the opening
The mistake came down to a matter of a few pixels in the wrong colour, and was changed within 30 minutes. But Mr Hwang refuses to take it personally.
"It was amazing, how visitors really scrutinise every detail. I appreciate that. They were thrilled to have their profession recognised."
His trip to London this week was to join a panel of judges examining the work of school children and teenagers who had each re-interpreted the logo along a theme of their choice.
Among those waiting to meet him were Westminster Kingsway students Christopher Frankland and Rafael Rizzolo, both 17, - Rafael, from Hackney, had a taste of some of the difficulties Mr Hwang faces.
He ran into some copyright problems with his first design - Homer Simpson hugging the "G" - so had to submit a dramatic fireworks piece.
The winner was Lisa Waiwaina, age 11, with her "Day of the Child" logo which fronted the Google UK homepage on Thursday, but Mr Hwang said the quality of entries was "mind blowing".
"I think the UK future in design is very bright," he added.