This example demonstrates a straightforward interactive message display built with React 16.10. It initially shows the static text “Welcome” and changes that text to “What can I do?” when the user clicks on the message. The application uses the React `useState` hook to manage the displayed string, and it renders the content into the DOM via `ReactDOM.render`. The code relies on the React and ReactDOM production UMD builds loaded from unpkg, with the app logic defined in an `index.js` module bundled into `bundle.js`. No external data source is used; the interaction is purely client-side state handling.