The occasional artistic "doodles" that replace the Google logo are seen by hundreds of millions of people. But who are the brains behind them?

A playable Les Paul guitar, a Pac-Man game and a keyboard in celebration of Robert Moog. These are just some of the many doodles that Google has displayed on its home page.

What started in 1998 as a stick figure drawing behind the letter "o" to show the team were out of the office, has now developed into intricate designs, games and artistic representations of famous figures and events.

There have been more than 1,000 doodles. They depict both the famous and the less well-known, they feature anniversaries and some more idiosyncratic tributes, and are increasingly becoming interactive and shareable.

How else would hundreds of millions of people been reminded of Amelia Earhart's 115th birthday or that Gideon Sundback was the inventor of the zip? On his 132nd birthday, Google placed a giant zip down their home page.

On every day of the 2012 Olympics, a new sport-themed doodle has lived above the search bar. One day it was synchronised swimming, another day users could practise shooting hoops against the clock.

Image caption The Olympics provided plenty of doodle inspiration

With every new doodle comes a raft of online news articles. The choice of doodle is always a noteworthy event, not least among bored office workers for whom the sketches offer a welcome splash of variety into their daily routine.

Whether one treats the doodles as art or design, they are among the most viewed examples in the world.

Despite the attention, there is little focus on the creators.

Watch the Charlie Chaplin doodle and you will get a glimpse, although in costume, of the team who call themselves "doodlers".

Image caption Google's creative team celebrated Dr Robert Moog's birthday with an interactive playable logo

They are seen by hundreds of millions of people. Some are put together in a few hours - others, like the Freddie Mercury tribute, take several months to complete. All are created by the handful of "doodlers" who sit in a small office in California.

The team's "creative lead", Ryan Germick, says he doesn't dwell on the idea of his work being viewed by such a mindboggling number of people.

"Human brains are not built to understand how hundreds of millions of people interpret something. For me it's more about seeing if I can make my colleagues laugh, or learn a new technique. Then I've done my job.

Image caption All the designs are created by the handful of "doodlers", including Ryan Germick and Jennifer Hom, who sit in a small office in California

"We just make sure we are representing art and technology in the best possible way."

He says they don't categorise themselves as artists or designers.

Breaking branding rules I love the doodles because from a branding perspective they break all the rules. One branding convention is to keep logos consistent. Because the Google brand is so pervasive and has a constant presence, the brand could become like wallpaper. The doodle is something surprising to keep things fresh and interesting. Tim Hill - The Brand Union Other companies would quickly lose their customers trust and familiarity if they changed their logo so often. Google can afford to change it because you are already where they want you to be - at their search page. A logo is only one part of a brand's identity. Google's identity is conveyed as much by its streamlined page design as anything else. You don't need to see the Google logo to know you are on their home page. Lisa Downey Merriam - Brand consultant

"We are the line between entertainment, arts, technology and graphic design. Those lines are very blurry."

The team, he says, are trying to deliver a maximum amount of joy with the limited resources available. Once designer Dennis Hwang was responsible for most of the doodles, but he has since moved on to other things. Individuals on the team don't usually take credit for their work.

"It's not about us as individuals, it's about Google as a culture," says Germick.

Most of those working on the technical side of the doodles do so under Google's 20% principle - where their day job is something else but a fifth of their time can be dedicated to a project.

Kris Hom, a technical engineer who used to be one of the 20% and only recently joined the doodle team full time, says the pinnacle for him was when his mother shared her score from one of the Olympic playable doodles.

The doodles are a way to "humanise the home page", says Hom.

The decision on what's featured, says Germick, is a "fairly democratic process" and is more about the element of surprise and finding a memory or person that's "a good fit", than celebrating common anniversaries. If they had to wait for Earhart's 150th birthday, for example, it would be a very long wait.

Image caption Doodle celebrating English archaeologist Howard Carter's 138th birthday

Suggestions from the public as well as ideas from Google offices in other countries play a big role. A lot of work is done using digital drawing tools, but sometimes a doodle originates as a physical painting. Doodler Jennifer Hom, painted the Gustav Klimt birthday doodle using faux gold leaf and oil paint, on canvas.

"I wanted to pay homage to Klimt with his most famous painting, The Kiss. I hope that our humble doodle does his brilliant legacy some justice," she wrote.

Image caption The process behind the doodles - including this design nod to Mark Twain - can be painstaking. Image caption Designs have become more sophisticated since the first Google doodle (above) in 1998. Image caption A video Google doodle was produced for Chaplin's birthday... Image caption ...and a design inspired by the Faberge egg creator Peter Carl Fabergé was showcased on the 166th anniversary of his birth. previous slide next slide

So are the doodles art?

"The point about art is that it is free of function," says Deyan Sudjic, director of London's Design Museum. "Design - which used to be called commercial art - is tied down by a functional obligation.

I see them as a playful way of commenting on what's going on but not as art. They are interesting because they start a conversation. I don't sit down as a fellow designer and critique and analyse them. They are disposable. Just because the audience are heavily exposed to them doesn't make them good or the most recognised pieces of design work. Many things are put in front of our nose, and while we may engage with them briefly, we also forget about them quickly. People go to Google for a purpose and the doodles may interrupt that journey. Paul Bailey Graphic designer and lecturer

"Andy Warhol began as an illustrator and made himself into an artist. The drawings he did as an illustrator sell for a lot, but not as much as his art does."

But graphic designer Si Scott - whose work includes corporate clients but also features in exhibitions - believes that these days design, including the doodles, is the new modern art.

Jasmine Montgomery, chief executive of marketing company Seven Brands, disagrees.

"Once you are being paid to harness your creativity to branding or advertising, it's not strictly art because it's serving a commercial master and not a purely creative master.

"The doodles are part of a well-designed customer experience. They are the equivalent of a hotel designing a nice lobby or a product coming in beautiful packaging," she argues.

It's hard to get away from the underlying corporate purpose of the doodles. They help Google play with its image - an image that occasionally comes under attack either because of privacy or accusations of tax avoidance.

The quirkier facts behind the doodles create "water cooler conversation", says branding consultant Lisa Downey Merriam, of Merriam Associates.

"The doodles are fun charming, playful and engaging, most of all they are relevant and sometimes even surprising - all this portrays some of the Google's personality."

And as long as the company retains its dominance, those sketches and scribbles - whether you see them as art, design, entertainment or hard-headed branding - will be a ubiquitous part of everyday browsing.