This example adds a freeform with five vertices to the first slide in the active presentation.
Set myDocument = ActivePresentation.Slides(1)
With myDocument.Shapes.BuildFreeform(msoEditingCorner, 360, 200)
.AddNodes msoSegmentCurve, _
msoEditingCorner, 380, 230, 400, 250, 450, 300
.AddNodes msoSegmentCurve, msoEditingAuto, 480, 200
.AddNodes msoSegmentLine, msoEditingAuto, 480, 400
.AddNodes msoSegmentLine, msoEditingAuto, 360, 200
.ConvertToShape
End With