One of the reasons all this works so well is that LittleBigPlanet is essentially 2D. When building, you can use background, middleground and foreground layers, but the Sackboys can only go between them when there's something there for them to interact with, like a ledge or grabbable object. The limited depth means building is a lot faster and simple, and the weirdly realistic physics guarantee that whatever you build, no matter how simple or complex, will work in some fashion. As an example, the developers showed off a giant, working adding machine they'd built in the game. Not much fun to play with, granted, but an interesting way to use the game nonetheless.

Primitive shapes aren't the only way to build, naturally. You'll also be able to work with more complex objects, which range from large composite shapes to actual 3D objects, such as balls, bits of fruit, spools of thread, gears, shells, those star-shaped lights from the trailer and dozens of other cool things. If you've seen it in the trailers, it'll be available for you to build with. And you'll be able to stick things to other objects with glue, bits of string or bolts, which can hang loose or be motorized to spin clockwise or counter-clockwise.

Above: The tank we built didn't quite look like this one, but you get the idea

To demonstrate, we were tasked with building an in-game tank, which enabled us to smash through the obstacles littering the demo level. We were given a a wooden, roughly tank-shaped background piece, and then splattered some glue onto it to stick a rectangular arch - to cover the wheels - onto it in the foreground. Then we stuck four spools of thread under the arch, fixed them in place with rotating bolts and hopped on as our shiny new juggernaut started trundling forward.

The tank was a pretty simple example of the sorts of things you can build in LittleBigPlanet; a more complex one is the Stompinator, a gigantic, clockwork developer creation that looks like a monstrous green dragon-dog and moves with clumsy help from legs mounted on big wheels. And these things aren't just there to give engineering students a reason to love the game; you'll be able to incorporate them into the levels you create (and share online, using the game's YouTube-inspired service), send them directly to friends or even use them as prizes to be won in multiplayer competitions.