# A computer built from 277k NAND gates

> NAND-16, a computer simulated from 277,248 NAND gates, with a CPU, memory, an assembler, a tiny OS, and a Tetris-style game running on it, on a 3D desk you can zoom through down to single gates. Opus 5.5 built it from one prompt over about 30 hours.

- Kind: Game
- Live game: https://somethingbig.ai/computer
- Page: https://meetreference.com/v/computer-built-from-277k-nand-gates/
- Ready-to-use agent handoff: https://meetreference.com/v/computer-built-from-277k-nand-gates/agent.txt
- Exact prompt as plain text: https://meetreference.com/v/computer-built-from-277k-nand-gates/prompt.txt
- Authorship: Not stated
- Made with: Not stated
- Model: Claude Opus 5.5
- Built with: not stated
- Style: Simulations; simulation, logic gates, cpu, 3d, retro computer, educational, zoom
- Shared by @mattshumer_ in X, Sep 27, 2026: https://x.com/mattshumer_/status/2104301990985498783
- Prompt fidelity: Verbatim. This is the complete prompt exactly as the creator published it.

## Before you start

Guidance from Reference, separate from the creator's instructions.

1. Read the reference and inspect the project, installed libraries, and available agent skills before writing code. Reuse suitable tools already present.
2. Prefer the creator-reported libraries and skills when they fit the task. Explain what useful additions help with, and install missing project dependencies or relevant skills from official sources when the environment and the user's existing permissions allow it. Respect the project's package manager and setup rules; do not ask again for routine setup already authorized.
3. Distinguish tools used by the creator from your own recommendations. A listed tool is not automatically required, and an empty tools or requirements list means the setup is unknown, not that nothing is needed.
4. Ask concise questions when missing inputs or choices materially affect the result: paid services, credentials, the user's assets, or a different production approach. Use existing answers and permissions; continue independent work while waiting.
5. If a useful library, skill, or service cannot be installed or used, explain an available alternative and its expected effect on quality, features, or effort. Get the user's choice before a material compromise; otherwise state the fallback and continue. Never silently simplify the result or claim to have used a tool you did not use.

## Recreating this game

These are the creator's published instructions, unedited.

To adapt it: Change "a game that runs on it" to the program you want to watch run, and keep "everything has to be real, the game has to run on your gates, not in javascript pretending." The sentence starting "visualize the whole thing in 3D" is what gives the zoom from the desk down to the gates.

## Prompt

```text
build a working computer from scratch, entirely in code, starting from individual logic gates. design the CPU, the memory, an assembler, a tiny operating system, and a game that runs on it. everything has to be real, the game has to run on your gates, not in javascript pretending. visualize the whole thing in 3D so i can play the game, then zoom all the way down through the chips into the gates and watch the signals flow while it runs. treat it like you're proving you could have invented computing yourself. go all out.
```

## What it looks like

Written by Reference from the video frames, not by the creator.

A dark, cyan-lit interface around a retro computer on a desk: a title card, the NAND-16 boot screen and a falling-block game on a CRT, then a zoom through the motherboard into glowing logic-gate diagrams.

- Color: Near-black navy with cyan and teal glow, amber-yellow on active gates, a cream CRT case on a wooden desk, and green-grey chips.
- Type: A clean sans-serif title ("A computer built from 277,248 NAND gates. Designed by Opus 5.5."), white captions in dark pills at the bottom ("It boots its own operating system", "Slow the clock to 4 Hz", "Fault Lab: break one gate"), blocky pixel text on the CRT, and small monospace readouts.
- Framing: 16:9. The scene fills the frame with readout panels in the top left, a clock control bar along the bottom, and a minimap in the bottom left; zoomed views show the gates as a flat glowing schematic.
- Structure: Title card, the boot menu (NANDTRIS, SNAKE, MONITOR, LIFE), NANDTRIS on the CRT, the motherboard with MASK ROM, SRAM, and VIDEO RAM chips, one full adder, the clock slowed to 4 Hz, bullet time with a signal chart, the Fault Lab, and a closing card, "Zoom in yourself.", with the site address.

Storyboard, nine frames spread across the video: https://meetreference.com/media/computer-built-from-277k-nand-gates/storyboard.webp

- Frame 1 at 3.5s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f1.webp
- Frame 2 at 10.4s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f2.webp
- Frame 3 at 17.3s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f3.webp
- Frame 4 at 24.2s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f4.webp
- Frame 5 at 31.1s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f5.webp
- Frame 6 at 38.0s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f6.webp
- Frame 7 at 44.9s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f7.webp
- Frame 8 at 51.8s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f8.webp
- Frame 9 at 58.7s: https://meetreference.com/media/computer-built-from-277k-nand-gates/f9.webp

## How it was made, per the creator

- One-shot: yes, a single prompt with no follow-ups
- Agent time: About 30 hours, running on its own in ultracode mode
- Reported spend: One Max plan; the creator says he had tokens to spare and didn't hit his limits once.
- Notes: The creator says it was "done from one prompt, completely autonomously, over ~30 hours in ultracode mode", with 277k logic gates in JavaScript, an OS on top, and games on the OS. He doesn't name the agent.

> This isn't a mockup... it's a computer.
> (@mattshumer_)

## Links

- Play game: https://somethingbig.ai/computer
- Watch: https://x.com/mattshumer_/status/2104301990985498783
- Original post: https://x.com/mattshumer_/status/2104301990985498783
- Reply with the prompt: https://x.com/mattshumer_/status/2104303934760218625