public class Auto : GLib.Object {
	private string farbe;

	public Auto() {farbe = "rot";}
	public Auto.faerben(string f) {farbe = f;}

	public void starten() {print("tucker");}
}

public class Ferrari : Auto {
	public void starten() {print("brumm");}
}

[...]

Auto bmw = new Auto.faerben("blau");

Ferrari f = new Ferrari();
Auto a = f;
a.starten();