Minecraft generates a bedrock floor at the bottom of the world from a random noise. Since it’s random, it can contain naturally generated unescapable regions – prisons. While small prisons are common, larger ones are hard to find – a Minecraft world is about 60 million by 60 million blocks, so locating these boxes is computationally difficult. So when I saw Bamboo Bot’s video on this concept covering a simple tool written in Java, I knew I had to give a try myself. I find this problem a good exercise for performance optimization because it has a limited scope, but also covers lots of topics. And it’s quite a head-scratcher due to its large scale! In this post, I’ll cover various surprising approaches and tricks I used, and hopefully you’ll be able to apply them to your projects.