Ссылка на обьект не указывает на экземпляр

Imports System 
Imports System.Drawing 
Imports System.Drawing.Drawing2D 
Imports System.Windows.Forms 
Public Class Form1 
    Private g As Graphics 
    Private pp As GraphicsPath 
    Private br As SolidBrush 
    Private pole As Point 
    Private center As Point 
    Private timer As Timer = New Timer() 
    Private pen As Pen = New Pen(Color.Red, 2) 
    Private curvepen As Pen = New Pen(Color.Blue, 1) With 
    { 
            .DashStyle = DashStyle.Dash 
    } 
    Private diameter As Single = 30.0F 
    Private a As Single = 10 
    Private phi As Single 
    Private pts As List(Of Point) 
    Private ptar As Point() 
    Public Sub New() 
        InitializeComponent() 
        g = Graphics.FromHwnd(Me.Handle) 
        pp = paraplan(450, 130, 20) 
    End Sub 
    Private Function paraplan(ByVal x As Integer, ByVal y As Integer, ByVal r As Integer) As GraphicsPath 
        Dim pts(,) As Integer = { 
                {x - 4 * r, y}, 
                {x - 2 * r, y - r}, 
                {x + 2 * r, y - r}, 
                {x + 4 * r, y}, 
                {x + 3 * r, y + r}, 
                {x + r, y}, 
                {x - r, y}, 
                {x - 3 * r, y + r}, 
                {x - 4 * r, y} 
        } 
        Dim pt(8) As Point 
        Dim typ(8) As Byte 
        For p As Integer = 0 To 8 
            pt(p).X = pts(p, 0) 
            pt(p).Y = pts(p, 1) 
            typ(p) = CByte(Math.Truncate(PathPointType.Line)) 
        Next p 
        Dim gp As New GraphicsPath(pt, typ) 
        Return gp 
    End Function 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
        g = Me.CreateGraphics() 
        Dim pp1 As GraphicsPath = paraplan(150, 80, 30) 
        Dim pen As New Pen(RandomColor(), 4.0F) 
        g.DrawPath(pen, pp1) 
    End Sub 
 
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click 
        g = Me.CreateGraphics() 
        g.ResetClip() 
        br = New SolidBrush(RandomColor()) 
        g.FillPath(br, pp) 
    End Sub 
 
    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click 
        Width = ClientSize.Width 
        Height = ClientSize.Height 
        Timer1.Interval = 5 
        Timer1.Start() 
    End Sub 
    Public Function RandomColor() As Color 
        Dim r, g, b As Integer 
        Dim bytes1(2) As Byte 
        Dim rnd1 As New Random() 
        rnd1.NextBytes(bytes1) 
        r = Convert.ToInt16(bytes1(0)) 
        g = Convert.ToInt16(bytes1(1)) 
        b = Convert.ToInt16(bytes1(2)) 
        Return Color.FromArgb(r, g, b) 
    End Function 
    Private Sub Reset() 
        phi = 0 
        pts.Clear() 
        ptar = Nothing 
    End Sub 
    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick 
        center = New Point() 
        center.X = CInt(((a / (Math.PI * 2)) * phi * Math.Cos(phi))) 
        center.Y = CInt(((a / (Math.PI * 2)) * phi * Math.Sin(phi))) 
        pts.Add(center) 
        ptar = New Point(pts.Count - 1) {} 
        pts.CopyTo(ptar) 
        Me.Refresh() 
        phi += 0.8F 
    End Sub 
 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
 
    End Sub 
 
    Private Sub Form1_Paint(sender As Object, e As PaintEventArgs) Handles MyBase.Paint 
        Try 
 
            If timer.Enabled Then 
 
                Using g As Graphics = e.Graphics 
                    g.TranslateTransform(pole.X, pole.Y) 
                    g.DrawEllipse(pen, center.X - diameter / 2, center.Y - diameter / 2, diameter, diameter) 
                    g.DrawCurve(curvepen, ptar) 
                    center.Offset(pole) 
                    If Not Me.ClientRectangle.Contains(center) Then Reset() 
                End Using 
            End If 
 
        Catch unusedException1 As Exception 
        End Try 
    End Sub 
End Class