Building a World Map with only 500 bytes

Building a World Map with only 500 bytes

Simon Willison’s Weblog

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4th July 2026 - Link Blog

Building a World Map with only 500 bytes ( via ) Iwo Kadziela (assisted by Codex) figured out a way to generate a credible ASCII world map using 445 bytes of data:

The key trick is to use deflate compression, which is then wired together using this neat snippet of JavaScript. I didn't know you could use fetch() with data: URIs like this:

fetch('data:;base64,1ZpLsgIxCEXnrM...==').then(
  r => r.body.pipeThrough(new DecompressionStream('deflate-raw'))
).then(
  s => new Response(s).text()
).then(
  t => b.innerHTML = '<pre style=font-size:.65vw>' + t
)

Posted

4th July 2026

at 11:09 pm

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This is a link post by Simon Willison, posted on 4th July 2026 .

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