return Scaffold(
  backgroundColor: Colors.white,
  appBar: AppBar(title: Text('Shadow Test')),
  body: Center(
    child: Container(
      width: 200,
      height: 200,
      decoration: BoxDecoration(
        color: Colors.blueAccent,
        boxShadow: [
          BoxShadow(blurRadius: 8.0),
          BoxShadow(color: Colors.white, offset: Offset(0, -16)),
          BoxShadow(color: Colors.white, offset: Offset(0, 16)),
          BoxShadow(color: Colors.white, offset: Offset(-16, -16)),
          BoxShadow(color: Colors.white, offset: Offset(-16, 16)),
        ],
      ),
    ),
  ),
);