Graphics exercise2

Public Class Form1
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim myGraphics As Graphics = PictureBox1.CreateGraphics
        Dim myPen0 As New Pen(Color.Blue, 5)
        Dim myPen1 As New Pen(Color.Gray, 0.5) : Dim myPen2 As New Pen(Color.Red, 2) : Dim myPen3 As New Pen(Color.Black, 2)
        Dim a, id As Integer
        Dim x1, y1, y2, angle As Single
        myGraphics.Clear(Me.BackColor)
        myGraphics.DrawRectangle(myPen0, x1, y1, 499, 499)

        myGraphics.DrawLine(myPen1, 50, 0, 50, 500)
        myGraphics.DrawLine(myPen1, 0, 250, 500, 250)
        a = 150

        myGraphics.TranslateTransform(50, 250)
        'For id = 0 To 360 Step 2
        'angle = id * Math.PI / 180
        'x1 = a * Math.Cos(angle) : y1 = a * Math.Sin(angle)
        'myGraphics.DrawLine(myPen2, 50, 100, 1, 1)
        'Next id

        For x1 = -50 To 450 Step 1
            y1 = -1 * Math.Cos(x1 * 7 * Math.PI / 500) * 100
            y2 = -1 * Math.Sin(x1 * 7 * Math.PI / 500) * 100
            myGraphics.DrawRectangle(myPen2, x1, y1, 1, 1)
            myGraphics.DrawRectangle(myPen3, x1, y2, 1, 1)
        Next
        myGraphics.Dispose()
    End Sub
    Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        Me.AutoSize = True
        PictureBox1.Top = 0 : PictureBox1.Left = 0
        PictureBox1.Width = 500 : PictureBox1.Height = 500
        Button1.Left = PictureBox1.Width + 50 : Button1.Top = 150
    End Sub
End Class