# Tower

> Runnel pack: a stone tower capped in ring-grained wood at the end of a long routed channel, on a glazed tray with a brass plate. A wooden ball rises out of the stone cup on top, rolls off the spout, drops into the channel, rides up the dish at the far end and rolls back into the tunnel at the tower's foot. Window light falls across it. Raymarched in WebGL.

- Slug: `runnel-tower`
- Category: [Asset packs](https://www.assembli.design/category/asset-packs.md)
- Subcategory: [Runnel](https://www.assembli.design/category/asset-packs/runnel.md) (`runnel`)
- Type: component
- Tags: 3d, webgl, raymarching, asset, wood, marble, brass, tower, marble-run, channel, ball
- npm dependencies: none
- shadcn/ui dependencies: none
- Added: 2026-10-24
- Live preview: https://www.assembli.design/preview/runnel-tower
- Page: https://www.assembli.design/components/runnel-tower

## Install

One-time setup (needs a subscription):

1. Add the registry to the project's `components.json`: `{"@assembli":{"url":"https://www.assembli.design/r/{name}.json","headers":{"Authorization":"Bearer ${ASSEMBLI_API_KEY}"}}}` (merge into `"registries"`).
2. Put an API key from https://www.assembli.design/account in `.env.local` as `ASSEMBLI_API_KEY=asm_…`.

Then install with the shadcn CLI (writes `components/runnel-tower/runnel-tower.tsx` and installs dependencies):

```bash
npx shadcn@latest add @assembli/runnel-tower
```

Registry item JSON: https://www.assembli.design/r/runnel-tower.json (send `Authorization: Bearer <api key>`)

## Code

> Component source needs an Assembli subscription ($12/month) and an API key sent as `Authorization: Bearer <key>`. To get one without copying anything, POST https://www.assembli.design/api/agent/login (or call the MCP tool connect_account), show the user the link it returns, and poll https://www.assembli.design/api/agent/token for the key. Or subscribe at https://www.assembli.design/pricing and create a key at https://www.assembli.design/account.