Just something I've made to pass the time. This simulator has three different types of matter- Wall (solid), Gas (gas, obviously), and Water (liquid). They all act differently. Simply select something by clicking on the buttons below. To change the amount of energy in gas, use the speed slider. Press C to clear. Try to see what you can make! Sorry water is kinda glitchy :(
I may update this- if I do, here's where the changelog would go. v1.0: 2/6/14 - initial release