A real computer,
built inside
a game

The full narration of the video.

Someone built a computer inside the game Minecraft. It's as big as a city, and takes just one step per second. How can blocks in a game turn into a computer? Start with a special block called redstone. Lay it out in a line. Pull a lever at one end, and a lamp lights up at the other.

It works like a wire. A signal is either there or not: the lamp is either on or off. Add one more little part: a redstone torch. Signal in, it goes dark; no signal, it lights up. Its whole job is to flip the signal. Put a few wires and torches together, and they can make tiny decisions. For example: the lamp lights only when both levers are pulled.

That's the smallest building block of a computer: a little switch that can only answer “yes” or “no.” The chip in your phone holds billions of these little switches. Each one is too small to see. In the game, one switch takes up several blocks. So a computer has to be built as big as a city.

Back in 2010, a player built the first machine in the game that could do math. Since then, more and more of these computers have been built. The most famous one is called CHUNGUS 2. One player built it over seven months, between school classes. It takes only one step per second. Yet it really can play Tetris and Snake. It can even draw math graphs.

One step a second is far too slow. So players wrote a speed-up program that makes redstone run over ten thousand times faster. In 2022, he and two friends went further: on this computer inside the game, they ran Minecraft itself. The screen is just 96 by 64 squares, in two colors. But you really can dig blocks and craft things in it.

Even sped up more than ten thousand times, it takes ten seconds to draw one picture. Without the speed-up, it takes days. In 2025, he built a little chatbot. It used more than 400 million blocks. Even forty thousand times faster, for one reply, you still wait about two hours. Is it a real computer? Yes. It works just like your phone: a huge pile of switches, flipping on and off, step by step. Just much slower.

And it's no hidden shortcut in the game. Every switch was placed by players, one block at a time. Next time you pick up your phone, think about this: behind that little screen are billions of switches, too, flipping billions of times a second. Seen anyone build something wild inside a game? Tell me in the comments.