Espoo, Finland (CNN) -- First, in 2009, there was "Angry Birds." Then came "Angry Birds Seasons," which put the birds in Christmas and other holiday scenes. Next was "Angry Birds Rio," set in South America. Finally, "Angry Birds Space" -- set, well, in space.
You get the point. Minus a few changes in scenery, all these wildly popular games from the Finnish company Rovio are essentially the same: Players slingshot disgruntled, wingless birds across a screen, hoping to take down the cartoon pigs that stole their eggs.
Meanwhile, Rovio has marketed "Angry Birds" cookbooks, theme parks, sweatshirts, plush toys, soda brands and a soon-to-be TV show based on this bird-pig drama.
In a business sense, it has worked. The apps have been downloaded 1 billion times, and 30% of the company's revenue comes from toys and other items. In 2011, Rovio reported earnings of $106 million, which impressed some financial analysts.
But when will it finally decide to invent something new?
Maybe quite soon, Ville Heijari, Rovio's vice president of franchise development, said in a recent interview at the company's waterside headquarters in a suburb of Helsinki.
Photos: Inside the Finnish company that makes "Angry Birds"
Heijari said Rovio has exhausted nearly all its options for marketing those now-ubiquitous ticked-off avians. Now the company has a team of designers working to create new prototype games that could be the company's sophomore franchise hit.
That will be no easy task. Rovio produced 51 failed apps and nearly went out of business before coming up with "Angry Birds" in 2009. The company was founded in 2003.