ほい
Private Sub Command1_Click()
  Me.ScaleMode = 1
  Dim x As Integer
  Dim i As Integer
  For i = 0 To 255
    Line (x, 0)-(x, Me.Height), RGB(0, i, 255 - i)
    x = x + 1
  Next
  For i = 0 To 255
    Line (x, 0)-(x, Me.Height), RGB(i, 255, 0)
    x = x + 1
  Next
  For i = 0 To 255
    Line (x, 0)-(x, Me.Height), RGB(255, 255 - i, 0)
    x = x + 1
  Next
End Sub