# How can a cliff in a block world hang right over your head?

- Series: [How It Spawns](https://miu.fm/howitspawns.md)
- Published: 2026-10-12
- Page: https://miu.fm/howitspawns/how-can-a-cliff-in-a-block-world-hang-right-over-your-head

## Story

How can a cliff in a block world hang right over your head?

In Minecraft's very first version, Markus Persson gave every column of ground one number: how high it goes. Three noise maps, one formula: (elevation + (roughness*detail))*64+64. It was fast. But one number per column means one top per column, and in his words, "there's no way for this method to generate any overhangs."

So he switched to 3D noise and read each value as a density: "anything lower than 0 would be air, and anything higher than or equal to 0 would be ground." To keep the bottom solid and the top empty, he added the height. Then he smoothed the lumps by sampling the noise only every 8 blocks across and 4 up, and blending in between. "Suddenly, the game had flat areas, smooth hills."

The world in this film is our own simplified version, built in code block by block. His exact formula, he wrote, was "a bit involved (and secret!)".

Which game's world should we cut open next?

Sources: Markus Persson, "Terrain generation, Part 1", The Word of Notch, March 9, 2011 (archived copy).
Not an official Minecraft video. Not approved by or associated with Mojang or Microsoft.
Sounds: Apple iMovie sound effects.

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