Here is what you want
Option Explicit
Public Sub BoundingBoxTest()
Dim oEnt As AcadEntity
Dim varPt As Variant
Dim MaxPoint As Variant
Dim MinPoint As Variant
Dim Vertices(0 To 9) As Double
Dim oPline As AcadLWPolyline
ThisDrawing.Utility.GetEntity oEnt, varPt, vbCrLf & "Select object"
oEnt.GetBoundingBox MinPoint, MaxPoint
Vertices(0) = MinPoint(0)
Vertices(1) = MinPoint(1)
Vertices(2) = MaxPoint(0)
Vertices(3) = MinPoint(1)
Vertices(4) = MaxPoint(0)
Vertices(5) = MaxPoint(1)
Vertices(6) = MinPoint(0)
Vertices(7) = MaxPoint(1)
Vertices(8) = MinPoint(0)
Vertices(9) = MinPoint(1)
Set oPline = ThisDrawing.ModelSpace.AddLightWeightPolyline(Vertices)
oPline.color = acYellow
End Sub
~'J'~