Demonstrates the use of virtual, override, sealed and new keywords on methods.

Virtual

public class Base
{
    public virtual void Method()
    {
        Console.WriteLine("Base (can be overridden.)");
    }

    public void CantOverride()
    {
        Console.WriteLine("Can't be overridden (but can be newed).");
    }
}

public class Overrider : Base
{
    public override void Method()
    {
        Console.WriteLine("Override (can be overridden.)");
    }

    public new void CantOverride()
    {
        Console.WriteLine("Can't be overridden (but can be newed).");
    }
}

public class SealedOverrider : Overrider
{
    public sealed override void Method()
    {
        Console.WriteLine("Sealed override (can't be overridden.)");
    }
}

public class Newer : SealedOverrider
{
    public new void Method()
    {
        Console.WriteLine("New");
    }
}