Imports System

​

Public Module Module1

    Public Sub Main()

        Dim m = New Main()

        m.World = New World()

        m.world.object1 = New ObjectWithMass()

        m.world.object1.name = "object1"

        m.world.object1.mass = 1

        m.world.object2 = New ObjectWithMass()

        m.world.object2.name = "object2"

        m.world.object2.mass = 2

        m.world.object3 = New ObjectWithMass()

        m.world.object3.name = "object3"

        m.world.object3.mass = 2

        Console.WriteLine(m.totalWorldMass())

        m.world.object1.mass = 100

        Console.WriteLine(m.totalWorldMass())

    End Sub

End Module

​

Public Class Main

    Public world As World

    Public ReadOnly Property totalWorldMass As Double

        Get

            Return world.object1.mass + world.object2.mass + world.object3.mass

        End Get

    End Property

End Class

​

Public Class World

    Public Property object1 As objectWithMass

    Public Property object2 As objectWithMass

    Public Property object3 As objectWithMass

End Class

​

Public Class ObjectWithMass

    Public Property name As String

    Public Property mass As Double

End Class

​