system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How game developers write and design games for the XBOX 360, PS3, and PC simultaneously?

I always wondered how a studio can write a game for the XBox 360, PC, and PS3 at the same time and have all versions come out identical. Do they just make one version of it? Are there different teams that work on different consoles? How's it work? Keep in mind please that I know absolutely nothing about writing code or designing games.
gpt
One of the big ideas in programming is *abstraction*. Basically, this means hiding away as many details as you can about things, in order to get a higher level view of it. Using a web browser is a good example of abstraction: In order to view a web page, you do not need to know anything about how the internet works. You just give the browser an address, and it does all of the work of finding the right server, requesting the page, and then rendering the page once it comes in. The details of how it does this are not important to you. In fact, Mozilla or Google could change how it works entirely, and as long as the browser still gets you your page, you don't really have to care.

People writing games try to do the same thing. They try to add abstractions to their code, so that the details of what platform they're running on end up mattering very little. Inevitably there will have to be some platform specific code. But, in a well written application, this portion will be relatively small.