I am a big fan of simulations, whether they are computer models or videogames. And I found two which I really liked.
The first one is a really complicated simulation of colliding galaxies (hat tip badastronomy):
The second one I am talking about is a video game which I really want. Anyone familiar with the Sim City franchise? I love city simulators and the way it allows me to just build whatever. Unfortunately, there are limitations, but one developer is making a city simulator called Cities XL that is taking away a lot of the limitations that existed. For example, no more grids and blocky roads, you can make them into various degrees of diagonal. There are much more improvements, which you can read in the developer’s blog I linked above. Hopefully, they won’t disappoint and break my heart. (hat tip simtropolis, great sim city fan site, oh and I found this really cool map of Hong Kong in it)
Posted by ibyea 
