Public Class Form1

    Dim x, y, dx, dy, s As Double

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        x += dx
        y += dy
        If x >= Me.ClientSize.Width - s Then
            x = Me.ClientSize.Width - s
            dx = -dx
        ElseIf x < 0 Then
            x = 0
            dx = -dx
        End If
        If y >= Me.ClientSize.Height - s Then
            y = Me.ClientSize.Height - s
            dy = -dy
        ElseIf y < 0 Then
            y = 0
            dy = -dy
        End If
        Me.Refresh()
    End Sub

    Private Sub Form1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        Dim g As Graphics = e.Graphics
        Dim x, y, s As Integer
        x = Me.x
        y = Me.y
        s = Me.s
        g.FillEllipse(Brushes.Navy, x, y, s, s)
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        x = 40
        y = 90
        dx = 1
        dy = 1
        s = 10
        Timer1.Enabled = True
    End Sub
End Class

























' MATERI ( pilih sampai nilai = 18 saja )
' 1. 3 poin ( tombol atas bawah (x) kiri kanan (y) mengubah kecepatan bola )
' 2. 3 poin ( tombol W S A D mengubah posisi bola )
' 3. 7 poin ( tombol + dan - menambah jumlah bola, max bola = 10, arah bola random )
' 4. 3 poin ( ketika window tidak aktif, bola berhenti )
' 5. 3 poin ( klik mouse pada suatu tempat mengubah posisi bola )
' 6. 3 poin ( tombol 1-9 mengubah ukuran bola ) --> HARAM u/ PR
' 7. 5 poin ( klik kanan mouse pada suatu tempat mengubah arah pergerakan bola )

' PR ( pilih sampai nilai = 9 saja )
' 1. 3 poin ( yang memantul = 3 buah gambar ) WAJIB
' 2. 5 poin ( gambar terdapat transparansi dan tidak ngeblink )
' 3. 3 poin ( 0-9 memilih gambar yg ada (diberi border) )
' 4. lain2 ( poin2 MATERI dibagi 2 di floor )