Rook example code

@hlship Take a look and see what you think.

This is work in progress because, at the very least, the [rook-example](https://github.com/curious-attempt-bunny/rook-example) repo code ([referenced by the markup](https://github.com/curious-attempt-bunny/aviso-documentation/blob/15dc1bf407f5f7d398bb3b9de950c10d38c02a4a/rook/example.ad#L10)) needs a proper home.