It's a mark of how quickly Android is taking off, especially in the US, that big iOS publisher Backflip is gearing up to bring its latest games to the platform.

Best known for its 24 million-download free casual game Paper Toss - which is already out on Android - company boss Julian Farrior told that activity had "blown up" over the past two months.

"The recent numbers we have been seeing in terms of downloads of Paper Toss are very exciting, as are daily usage numbers and the mobile advertising revenue," he said.

Eventually, Backflip expects to bring all its free games to Android, with most recent releases Strike Knight, Graffiti Ball, and Ninjump due first.