app-structure.js

export const App = () => {
 const [notification, setNotification] = useState('') // where should this state live?
 return (
   <Hierarchy1>
     <Component1>
       <Notification/> // renders a notification
     </Component1>
   </Hierarchy1>
   <Hierarchy2>
     <Component2>
       <FormComponent/> // needs to set the notification
     </Component2>
   </Hierarchy2>
 )
}