# Cube Letter Swap

> Rotating word where every letter is a real 3D prism: on each tick the letters roll a quarter turn in a staggered wave with a little overshoot, revealing the next word on the face below, with light falling off as faces turn away. Works inline in any headline. Rolls up or down, with an optional mode that sets each letter on a tile. Screen readers hear each word once.

- Slug: `cube-letter-swap`
- Category: [3D](https://www.assembli.design/category/3d.md)
- Type: component
- Tags: 3d, text, rotating-words, headline, prism, typography
- npm dependencies: motion
- shadcn/ui dependencies: none
- Added: 2026-10-15
- Live preview: https://www.assembli.design/preview/cube-letter-swap
- Page: https://www.assembli.design/components/cube-letter-swap

## 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/cube-letter-swap/cube-letter-swap.tsx` and installs dependencies):

```bash
npx shadcn@latest add @assembli/cube-letter-swap
```

Registry item JSON: https://www.assembli.design/r/cube-letter-swap.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.