Public MustInherit Class Geometric2D
    Protected pntPoint As Point
    Protected r As Double
    Protected a, b As Double
 
    Structure Point
        Private intX, intY As Double
 
        Public Property X() As Double
            Get
                Return intX
            End Get
            Set(ByVal value As Double)
                intX = value
            End Set
        End Property
 
        Public Property Y() As Double
            Get
                Return intY
            End Get
            Set(ByVal value As Double)
                intY = value
            End Set
        End Property
    End Structure
 
    MustOverride Function GetFläche() As Double
 
    MustOverride Function GetUmfang() As Double
End Class