Patterns is a Minecraft-esque "break things and then build with them" type game that adds more varied geometry and a physics engine to the mix. Under development by Linden Lab, most famous for the sort of MMO, sort of 3D art tool Second Life, an early build of the game is now available for $10 from their official site. The developers say that, like Minecraft, this represents and early buy-in price that will also guarantee you access to future updates as the game takes shape.
Patterns lets you play a man made of triangles as he combines triangles into non-triangle shapes to build mega structures like some sort of mad triangle god. It's being developed by Second Life creators, Linden Labs in partnership with Free Range Games. It'll let you "explore caverns and valleys, while you harvest substances with real world densities." You can use those harvested substances to construct
the greatest triangle in the universe bridges and the like.
There is a beta, which you can sign up for on this Linden Labs page. Linden Labs CEO Rod Humble provides a visual introduction to the world of patterns in this debut trailer.