Microsoft is launching a beta version of Project Spark for its Xbox One console today. The game-maker project originally launched in test form on Windows 8.1 in December, and the expansion to the Xbox One today allows allow developers, enthusiasts, and gamers to build a game within a game that runs across PCs, tablets, and Xbox consoles. Players can build custom worlds, characters, and animations from the Xbox One, and continue editing or playing them on a Windows 8.1 PC. It’s similar in concept to Sony’s LittleBigPlanet, but Microsoft continues to make use of its Kodu platform efforts, while pushing SmartGlass integration to allow players to interact with games from a tablet while they build and play on an Xbox One.