Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim V_Region As Object

        ' declare variables
        Const PI = 3.14159265358979
        Dim line1 As Object
        Dim line2 As Object
        Dim line3 As Object
        Dim arc1 As Object
        Dim center1(2) As Double
        Dim point1(0 To 2) As Double
        Dim point2(0 To 2) As Double
        Dim point3(0 To 2) As Double
        Dim point4(0 To 2) As Double

        point1(0) = 10 : point1(1) = 10 : point1(2) = 0
        point2(0) = 50 : point2(1) = 10 : point2(2) = 0
        point3(0) = 50 : point3(1) = 20 : point3(2) = 0
        point4(0) = 10 : point4(1) = 20 : point4(2) = 0

        line1 = V_AutoCad.ActiveDocument.ModelSpace.AddLine(point1, point2)
        line2 = V_AutoCad.ActiveDocument.ModelSpace.AddLine(point3, point4)
        line3 = V_AutoCad.ActiveDocument.ModelSpace.AddLine(point4, point1)
        center1(0) = line1.EndPoint(0) : center1(1) = line1.EndPoint(1) + 5
        center1(2) = 0
        arc1 = V_AutoCad.ActiveDocument.ModelSpace.AddArc(center1, 5, 3 / 2 * PI, 1 / 2 * PI)
        ' make array for region
        Dim arrayobj(3) As AcadEntity
        arrayobj(0) = line1
        arrayobj(1) = arc1
        arrayobj(2) = line2
        arrayobj(3) = line3
        ' make the region from the array

        V_Region = V_AutoCad.ActiveDocument.ModelSpace.AddRegion(arrayobj)
       

    End Sub