Principia is an almost limitless build-'em-up that's out right now for iPad and iPhone
Principia has been out for Android for a few months now. It's a deep, involving build-'em-up with a focus on creativity and community. Well, iOS gamers can finally get their hands on it today.
This game is an aspiring engineer's dream, for it tasks you with creating contraptions out of different chunks of moveable machinery.
There's huge scope for experimentation here. And you can share the creations you've made with other users across the globe. You can even make your own games in the flexible freeform mode.
Or just build a giant robot. Who doesn't want to do that?
Principia is out right now on the App Store, and costs £2.49 / $3.99.