From The Powder Toy:
The Powder Toy Portable is a game of physics and fluid mechanics. You can play with different materials whose properties and influences are simulated. The Powder Toy is a free physics sandbox game, which simulates air pressure and velocity, heat, gravity and a countless number of interactions between different substances! The game provides you with various building materials, liquids, gases and electronic components which can be used to construct complex machines, guns, bombs, realistic terrains and almost anything else. You can then mine them and watch cool explosions, add intricate wirings, play with little stickmen or operate your machine.
What's new in this version:
Version 87.2 has fixed lua graphics function crash on error, changed the menusection of some elements, and improved readability of tooltips.