Public Function MakeTriangle(c As Control) As Region
    Dim mp As New System.Drawing.Drawing2D.GraphicsPath
    Dim pts(2) As Point
 
    pts(0) = New Point(c.Width \ 2, 0)
    pts(1) = New Point(0, c.Height)
    pts(2) = New Point(c.Width, c.Height)
 
    mp.AddPolygon(pts)
    Dim rg As New Region(mp)
    mp.Dispose()
    Return rg
End Function