TinyBuild has released a free version of its Silver Award-winning puzzler Divide By Sheep on Android.

The reason for doing this is to experiment with a different monetisation system.

Previous versions of Divide By Sheep (and most of tinyBuild's published games - Fearless Fantasy, Snail Bob 2, Spoiler Alert) are premium. That means you pay upfront for the game.

But for this free version of Divide By Sheep the revenue comes from putting adverts in front of players.

"I've been seeing more and more successful - and fun - mobile games adopt ads-based monetization, and we've been really curious to try it," says tinyBuild's Alex Nichiporchik.

"I found myself not mind watching an ad if I fail at a game, and Divide By Sheep is our first experiment."

Does this mean that tinyBuild's games will be free and ad-supported in the future? It seems doubtful, but maybe the studio will offer alternative free versions of its games as it's doing with Divide By Sheep.

Then again, it's possible - perhaps it depends on how successful this experiment ends up being.

You can download the free version of Divide By Sheep on Google Play.

The premium version of the game is available for £2.29 / $2.99 on the App Store and Google Play.