'A tractor'.. (or 'The Universal', either way)... is an online game for PC. Play games, explore the galaxy, or make your own world with your own game design. Various game types are available - including complex social economies - and you can play it all for free. If you're the creative type you'll find extensive in-game tools and a powerful scripting engine to let you create new game ideas. Or you can just mess around and blow each other into ostriches. It's all cool, whatever.
A view from one of the core worlds, demonstrating the latest grass rendering system and water shaders.
Omg legit foliage! Are those shaders I see out on the water?
I have now passed 'Amateur Shader Graphics Programmer (Stage 1)' !
(p.s. check out the sand and bloom in Youtu.be :] )