Private Sub PictureBox1_MouseUp(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseUp
        Dim myGraphics As Graphics = PictureBox1.CreateGraphics
        Dim myPen As Pen
	Dim offsetX As Integer = e.X-startX
	Dim offsetY As Integer = e.Y-startY

        myPen = New Pen(Brushes.DarkMagenta, 20)
        myGraphics.DrawLine(myPen, startX, startY, startX+offsetX, startY+offsetY)
        myGraphics.DrawLine(myPen,startX+offsetX, startY+offsetY, startX-offsetY, startY+offsetX)
        myGraphics.DrawLine(myPen,startX, startY, startX-offsetY, startY+offsetX)
    End Sub