Universe Sandbox isn't a game per se; there are no bosses, aims or levels, merely an accurate model of astronomical bodies for you to fiddle with. It's really more of a toy – the virtual equivalent of a configurable orrery, except hugely more complex than any mechanical system.That complexity is one of the key attractions that Universe Sandbox possesses. Using the vast range of variables and tools at your disposal you can create some enormously convoluted displays of physics, bending cosmic laws to your will out of nothing more than a desire to see pretty patterns form on your screen.There are a series of example experiments to help ease you into the level of curiosity that Universe Sandbox requires – each one acting as a tutorial – but the real fun lies in creating your own simulations. The camera is a little fiddly at times, but my biggest complaint is that the simulator doesn’t come with any sound or music. While I appreciate that’s realistic, given the lack of orchestras in the vacuum of space, it would have been nice to have some ambient music quietly twinkling away in the background.Still, it’s hard to get too dissatisfied with Universe Sandbox when you factor in both the fact that it’s a one-man labour of love and that it’s available at a bargain price. If nothing else it offers something uniquely interesting and fun, which is quick to inspire imagination and creativity, even if it lacks the educational aspect that you might expect.