Public Class MyBaseClass
    Implements ICloneable

    Private my_base_var As Integer

    Public Function Clone() As Object Implements System.ICloneable.Clone
        Dim new_base_class As MyBaseClass = New MyBaseClass
        new_base_class.my_base_var = my_base_var
        Return new_base_class
    End Function

End Class

Public Class MySubClass
    Inherits MyBaseClass
    Implements ICloneable

    Private my_sub_var As Integer

    Public Overloads Function Clone() As Object Implements System.ICloneable.Clone
        Dim new_sub_class As MySubClass = CType(MyBase.Clone, MySubClass)    ' (1)
        new_sub_class.my_sub_var = Me.my_sub_var
        Return new_sub_class
    End Function

End Class

Dim new_sub_class As MySubClass = MyBase.Clone