() => {
  class MyForm extends Component {
    constructor(props) {
      super(props);

      this.state = {
        value: 'quartz'
      };

      this.handleChange = this.handleChange.bind(this);
    }

    handleChange(event) {
      this.setState({
        value: event.target.value
      });
    }

    render() {
      return (
        <DemoForm>
          <Radio
            name="mineral"
            label="Quartz"
            value="quartz"
            checked={this.state.value === 'quartz'}
            onChange={this.handleChange} />
          <Radio
            name="mineral"
            label="Magnetite"
            value="magnetite"
            checked={this.state.value === 'magnetite'}
            onChange={this.handleChange} />
        </DemoForm>
      );
    }
  }

  return <MyForm />;
}