protected void Page_Load(object sender, EventArgs e)
{
SampleClass sc = new SampleClass();
IControl ctrl = (IControl)sc;
ISurface srfc = (ISurface)sc;
// The following lines all call the same method.
sc.Paint();
ctrl.Paint();
srfc.Paint();
sc.Fly();
ctrl.Eat();
sc.Eat();
sc.Hit();
}