# Swallowtail Hero

> Centered hero with a swarm of CSS 3D swallowtail butterflies that share one 3D context with the headline, so they fly both in front of and behind it. SVG wings flap in bursts and glides, bodies bank into turns, the cursor startles nearby ones and a click scatters the swarm. It bursts out from the center on load. No WebGL.

- Slug: `swallowtail-hero`
- Category: [Heroes](https://www.assembli.design/category/heroes.md)
- Type: block
- Tags: 3d, css-3d, perspective, butterflies, playful, interactive, nature
- npm dependencies: motion, lucide-react
- shadcn/ui dependencies: button
- Added: 2026-10-15
- Live preview: https://www.assembli.design/preview/swallowtail-hero
- Page: https://www.assembli.design/components/swallowtail-hero

## 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/swallowtail-hero/swallowtail-hero.tsx` and installs dependencies):

```bash
npx shadcn@latest add @assembli/swallowtail-hero
```

Registry item JSON: https://www.assembli.design/r/swallowtail-hero.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.