Public Class Form1

    Private Sub TrackBar1_Scroll(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TrackBar1.Scroll
        Dim c1, c2, numberOfBoxes, numberOfRows As Integer
        Dim paper As Graphics
        Dim myPen As Pen = New Pen(Color.Blue, 2)
        numberOfBoxes = TrackBar1.Value
        numberOfRows = TrackBar2.Maximum - TrackBar2.Value
        paper = PictureBox1.CreateGraphics()
        paper.Clear(Color.Gold)
         For c2 = 1 To numberOfRows
            For c1 = 1 To numberOfBoxes
                paper.DrawRectangle(myPen, 20 * c1 - 10, 20 * c2 - 10, 12, 12)
            Next
        Next
    End Sub

    Private Sub PictureBox1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PictureBox1.Click

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub TrackBar2_Scroll(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TrackBar2.Scroll
        Dim c1, c2, numberOfBoxes, numberOfRows As Integer
        Dim paper As Graphics
        Dim myPen As Pen = New Pen(Color.Blue, 2)
        numberOfBoxes = TrackBar1.Value
        numberOfRows = TrackBar2.Maximum - TrackBar2.Value
        paper = PictureBox1.CreateGraphics()
        paper.Clear(Color.Gold)
        For c2 = 1 To numberOfRows
            For c1 = 1 To numberOfBoxes
                paper.DrawRectangle(myPen, 20 * c1 - 10, 20 * c2 - 10, 12, 12)
            Next
        Next
    End Sub

End Class