public class MereMortalProgrammer
    {
    }

    public class Expert : MereMortalProgrammer
    {
    }

    public class Blog
    {
        public void DailyWork()
        {
            Expert e = this.Pose() as Expert;
        }

        public MereMortalProgrammer Pose()
        {
            return new Expert();
        }
    }