気持ち悪い。
何でだろう！
簡単な下のコードで、楕円の横幅がどんどん広がってくる。


'円の中心位置
Dim m_posX As Long

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
m_posX = 100
Timer1.Enabled = True
End Sub

Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
m_posX = m_posX + 1
'図形描画のために変数GraphicsFunを定義する
Dim GraphicsFun As System.Drawing.Graphics
GraphicsFun = Me.CreateGraphics
GraphicsFun.Clear(BackColor)
'ブラシの色(赤)を指定して図形(円)を描く
Dim BrushColor As New SolidBrush(Color.Red)
GraphicsFun.FillEllipse(BrushColor, (m_posX - 100), 50, (m_posX + 100), 250)
GraphicsFun.Dispose()
End Sub