Public Class Form1
    Dim feld(6, 7) As Int32
    Dim WithEvents Pb As New PictureBox
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.ClientSize = New Size(350, 300)
        Pb.Dock = DockStyle.Fill
        Pb.Parent = Me
    End Sub
 
    Private Sub Pb_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Pb.MouseDown
        Dim y As Int32 = e.Y \ 50
        Dim x As Int32 = e.X \ 50
        If feld(y, x) = 0 Then
            If e.Button = Windows.Forms.MouseButtons.Left Then
                feld(y, x) = 1    'schwarz
            Else
                feld(y, x) = 2    'gelb
            End If
            Pb.Invalidate()
            'Ergebnis auswerten
        End If
    End Sub
 
    Private Sub Pb_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles Pb.Paint
        e.Graphics.Clear(Color.Aqua)
        e.Graphics.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
        For y As Int32 = 0 To 5
            For x As Int32 = 0 To 6
                e.Graphics.DrawRectangle(Pens.Black, x * 50, y * 50, 50, 50)
                Select Case feld(y, x)
                    Case 1
                        e.Graphics.FillEllipse(Brushes.Black, 5 + x * 50, 5 + y _
                          * 50, 40, 40)
                    Case 2
                        e.Graphics.FillEllipse(Brushes.Yellow, 5 + x * 50, 5 + _
                          y * 50, 40, 40)
                End Select
            Next
        Next
    End Sub
End Class