I couldn't change color of diagonal line in 16*16 label matrix. What's my false in here? : 16*16 matrix is coming to my screen when i start the program. But when i click diagonal button, diagonal line  isn't red. that is not change.

my codes :

Public Class Form1
    Dim etk As New Label 'i define the matrix as etk

    Public Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For i = 0 To 15
            For j = 0 To 15
                Dim etk As New Label
                Me.Panel.Controls.Add(etk)
                etk.Name = i
                etk.Tag = j
                etk.Size = New Size(26, 26)
                etk.BackColor = Color.Black
                etk.Location = New Point(30 * i + 10, 30 * j + 10)
            Next
        Next
    End Sub

    Private Sub diagonal_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
        Timer1.Enabled = True
        For i = 0 To 15
            For j = 0 To 15
                etk.Name = i
                etk.Tag = j
                If i = j Then
                    etk.BackColor = Color.Red
                End If
            Next
        Next
    End Sub
End Class


thanks for your interests..