I stumbled upon a fun little web toy written in Java. You can create particles of various substances and they are released into a gravitational well that pulls them towards the center of the display. The substances interact in various ways, and you can sit back and watch the simuation run. For instance, you can drop some salt on the screen, and then add water and watch the salt melt. Dropping “seeds” will cause plants to grow, but add a touch of fire and the plants will burn away. By combining the substances, you can achieve effects which take a couple minutes to come into equilibrium.
This game doesn’t tell a story, and I’m not entirely sure what the objective is, but I enjoyed poking at it for what I thought was a few minutes, but was probably more like half and hour.