Public Class Form1
    Private img As New Bitmap(500, 500)            '描画用ビットマップ
    Private g As Graphics                         'グラフィック変数
    Private R As Double = 200                      '半径
    Private X0 As Double = 250, Y0 As Double = 250 '中心座標
    Private N As Integer                           '実行中角数
    Private dTH As Double = Math.PI / 6            '角数の増分値
    Private TH As Double                           '回転角度
    Private PC(8) As Pen                           '描画用Pen
    Private PWhite As Pen                          'White Pen
    Private BRed As Brush                          'Red Brush
    Private Sub initData()
        PC(0) = New Pen(Color.FromArgb(&HFF, &H0, &H0))
        PC(1) = New Pen(Color.FromArgb(&HFF, &H77, &H0))
        PC(2) = New Pen(Color.FromArgb(&H77, &H77, &H0))
        PC(3) = New Pen(Color.FromArgb(&H0, &H90, &H0))
        PC(4) = New Pen(Color.FromArgb(&H0, &H77, &H0))
        PC(5) = New Pen(Color.FromArgb(&H0, &H77, &H77))
        PC(6) = New Pen(Color.FromArgb(&H0, &H0, &HFF))
        PC(7) = New Pen(Color.FromArgb(&H77, &H0, &HFF))
        PC(8) = New Pen(Color.FromArgb(&HFF, &H0, &HFF))
        PWhite = New Pen(Color.White)
        BRed = New SolidBrush(Color.Red)
    End Sub
    Private Sub drawDLine(X1 As Double, Y1 As Double, X2 As Double, Y2 As Double, P As Pen)
        Dim IX1 As Integer = X1 + 0.5, IY1 As Integer = Y1 + 0.5
        Dim IX2 As Integer = X2 + 0.5, IY2 As Integer = Y2 + 0.5
        g.DrawLine(P, IX1, IY1, IX2, IY2)
    End Sub
    Private Sub fillDCircle(X0 As Double, Y0 As Double, R As Double, B As Brush)
        Dim IX0 As Integer = X0 + 0.5, IY0 As Integer = Y0 + 0.5
        Dim IR As Integer = R + 0.5, IR2 As Integer = 2 * R + 0.5
        g.FillEllipse(B, IX0 - IR, IY0 - IR, IR2, IR2)
    End Sub
    Private Sub DrawPic()
        Dim X1 As Double, X2 As Double, Y1 As Double, Y2 As Double
        Dim i As Integer
        g = Graphics.FromImage(img) : g.Clear(Color.Black) '描画クリア
        Dim DY As Double, DX As Double, XR2 As Double, YR2 As Double
        X2 = X0 + R * Math.Cos(TH) : XR2 = X2
        Y2 = Y0 - R * Math.Sin(TH) : YR2 = Y2
        DY = 4 * Math.Sin(TH) : DX = 4 * Math.Cos(TH)
        i = 0 : Y1 = Y0
        For X1 = X0 To X0 + R Step 4
            drawDLine(X1, Y1, X2, Y2, PC(i Mod 9))
            X2 = X2 - DX : Y2 = Y2 + DY : i = i + 1
        Next
        drawDLine(X0, Y0, XR2, YR2, PWhite)
        drawDLine(X0, Y0, X0 + R, Y0, PWhite)
        fillDCircle(XR2, YR2, 5, BRed)
        PictureBox1.Image = img : g.Dispose()
    End Sub
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        TH = 0
        Timer1.Enabled = True
    End Sub
    Private Sub singleDraw()
        DrawPic()
        If TH >= 2 * Math.PI * 0.99999 Then TH = 0
        TH = TH + dTH
    End Sub
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        TH = 0
        initData()
    End Sub
    Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
        singleDraw()
    End Sub
    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        Timer1.Enabled = False
    End Sub
    Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
        singleDraw()
    End Sub
End Class