I am reminded of this 4 kilobyte demo: <a href="https://www.youtube.com/watch?v=jB0vBmiTr6o" rel="nofollow">https://www.youtube.com/watch?v=jB0vBmiTr6o</a><p>(Source code and discussion at <a href="https://news.ycombinator.com/item?id=11848097" rel="nofollow">https://news.ycombinator.com/item?id=11848097</a> ; explanation at <a href="http://www.iquilezles.org/www/material/function2009/function2009.pdf" rel="nofollow">http://www.iquilezles.org/www/material/function2009/function...</a> )<p>although the flight sim is a little more interesting from a technical perspective, since it's interactive and also not using the GPU to do most of the computation.<p>Also, despite the source code being obfuscated, observe that that "external symbols" which are still visible, e.g. XDrawLine, XSetForeground, etc. already give a pretty good overview of how it does what it does --- and in general, when reverse-engineering or analysing software, inspecting where the "black box" interacts with the rest of the world is an important part of understanding it.