Why one tile a day?

Most generative worlds appear all at once. You press a button and a whole continent unfolds in a second. One Tile a Day does the opposite: the island is only allowed to change once per day, and only by a single tile.

A commit as a unit of time

The island lives in a public GitHub repository. Its entire state is one file, world/world.json, and every day exactly one commit changes it. The commit history is not a side effect – it is the story:

Day 3: Grass spreads on the western dunes
Day 2: Land rises off the north-west coast
Day 1: Land rises off the north-east coast
Day 0: A sandbank in the open sea

Because the map inside world.json is stored as rows of characters, a daily diff is literally one character that changed – ~ becomes . when a strip of sand rises from the sea.

Slow on purpose

One tile is almost nothing. That is the point. You cannot binge this island; you can only come back. After a week there is a meadow, after a month a first house and someone living in it, after a year a village with a harbour, a lighthouse and a library – every one of those things placed on a specific day, for a reason, with a line of lore that says why.

Rules instead of randomness

A world that only grows by chance turns into noise. This island follows rules: a house needs land around it, a harbour needs a coast and three houses, the lighthouse needs rock by the sea. The code enforces them – the routine can only choose among legal changes. Chapter 2 shows all of them.

Open by default

Everything that shapes the island is in the repository: the rules, the renderer, the prompt the routine follows (ROUTINE.md) and the complete history. The island is transparently AI-maintained – Claude writes the lore and makes the daily choice, and every commit says so.

You are welcome to read along, fork it, or start an island of your own.