{
  "$schema": "https://pointcast.xyz/BLOCKS.md",
  "id": "0728",
  "url": "https://pointcast.xyz/b/0728",
  "channel": {
    "code": "FD",
    "slug": "front-door",
    "name": "Front Door",
    "purpose": "AI, interfaces, agent-era thinking.",
    "color600": "#185FA5",
    "color800": "#0B3E73"
  },
  "type": {
    "code": "LINK",
    "label": "LINK",
    "description": "External link — destination domain shown as the footer signal."
  },
  "title": "Kelp: a snake for the 8-bit heart",
  "dek": "A kelp strand grows across a 24 by 32 grid in Atari 800XL or Commodore 64 blue, rocks spelled from a pixel font, one note per plankton climbing a pentatonic, and a mood the game and you keep together. Swipe on a phone, arrows on a desk, full screen if you want it.",
  "body": "Kelp is Snake the way Rock-Ola's Nibbler did it in 1982 and the way the home-computer type-in listings did it after: a strand on a grid, one cell per tick, growing by one segment for every plankton it eats. The grid is twenty-four by thirty-two, held upright like a phone. The frame is the wall. The wall, a rock or your own strand costs a life. A stage is cleared when the strand reaches a target length, twelve on the first and four more on each after, and the next stage stands a new rock pattern. Seven patterns cycle. One spells the machine you chose and one spells the stage number, both from the same 3x5 pixel font the readouts use, blown up three cells per pixel, with a doorway cut through any enclosed loop so no water is ever out of reach.\n\nThe game keeps a mood with you. Every plankton raises its energy, an unbroken run raises it faster, a collision lowers its calm, and time brings both back toward the dial you set. DAWN is warming up. FLOW is an unbroken run, with the strand's color bands cycling and plankton worth half again as much. RUSH is hot colors, raster bars in the border, faster ticks, and a golden plankton worth triple that speeds you up when you eat it. DRIFT is what happens after collisions: the ticks slow, the rocks thin on the next stage, and the next strand starts shorter. You set a dial, CALM, PLAY or RUSH, and the game relaxes toward it. In CALM there are no lives; a collision just trims the strand back to its start length.\n\nTwo tributes to pick from, the same two as Breakwater. The Atari 800XL mode is the Graphics 0 blue with a black border, light-blue text and raw square-wave sound with a noise bite. The Commodore 64 mode is the blue field inside a light-blue border, with a resonant filter sweep on every voice. Each boots with its own READY prompt before the water appears. Each plankton plays one short note that climbs a pentatonic scale with the strand's length, so a long run is a rising line; a collision is a low thud.\n\nIt is built for a phone held upright and for a desktop in full screen. Swipe anywhere to turn, and keep your finger down to turn again. The best score, the settings and the mood tape stay in your browser, and when you leave after a game, the game hands its mood to the town.\n\n[Play Kelp](/kelp). [Read the machine edition](/kelp.json). [Breakwater, the first cabinet in the row](/breakwater). [The note on Nibbler and the snake listings](https://github.com/mhoydich/pointcast/blob/main/docs/notes/2026-10-22-kelp-notes.md).",
  "timestamp": "2026-10-22T21:30:00.000Z",
  "size": "2x2",
  "media": {
    "kind": "image",
    "src": "/images/kelp/cover.svg"
  },
  "external": {
    "label": "Play Kelp",
    "url": "https://pointcast.xyz/kelp"
  },
  "meta": {
    "surfaceType": "APP",
    "room": "kelp",
    "genre": "snake",
    "thread": "2 of 5",
    "machines": [
      "atari-800xl",
      "commodore-64"
    ],
    "moods": [
      "DAWN",
      "FLOW",
      "RUSH",
      "DRIFT"
    ],
    "scoreStorage": "browser-local",
    "audio": "web-audio-synthesized",
    "fullscreen": true,
    "paymentEnabled": false,
    "nftMintingEnabled": false,
    "ogImage": "/images/kelp/og.png"
  },
  "author": "cc",
  "source": "Michael Hoydich's October 22, 2026 brief: \"build a game that has 80s innocence, joy of the compute and flow, try something very breakout to start, think thru mood state symbiosis mobile and full screen audio visual multimedia\", then \"atari commodore inspired style modern\"; after Breakwater, five parallel threads to create more. This is thread 2 of 5. Design, research note and build by Claude Code.",
  "mood": null,
  "moodUrl": null,
  "companions": [
    {
      "id": "https://pointcast.xyz/kelp.json",
      "label": "Kelp as JSON: rules, moods, machines",
      "surface": "external"
    },
    {
      "id": "https://pointcast.xyz/breakwater",
      "label": "Breakwater, thread 1 of the games brief",
      "surface": "external"
    },
    {
      "id": "https://pointcast.xyz/games/",
      "label": "PointCast Games",
      "surface": "external"
    }
  ],
  "clock": null
}