怎么用VB做这个交通灯

准备3张图片：

工程窗口中加入一个Picture1，在Picture1中增加一个Label1，在窗口中增加一个定时器Timer1

运行情况：

程序代码：

Dim zt As Long, js As Long

Private Sub Form_Load()

Me.Caption = "交通灯"

zt = 0

js = 0

Label1.ZOrder 0

Label1.Top = 250

Label1.FontSize = 40

Label1.ForeColor = vbWhite

End Sub

Function xsjtd(ByVal cl As String, ByVal sz As Integer)

Me.Picture1.Picture = VB.LoadPicture(App.Path & "\" & cl & ".jpg")

If sz < 10 Then

Label1.Left = 480

Else

Label1.Left = 240

End If

If cl = "红" Then

Label1.Top = 250

ElseIf cl = "黄" Then

Label1.Top = 1750

Else

Label1.Top = 3250

End If

Label1.Caption = sz

End Function

Private Sub Timer1_Timer()

Dim n As Integer

If zt = 0 Then

js = js + 1

n = 30 - js

Call xsjtd("红", n)

If js >= 30 Then

zt = 1

js = 0

Exit Sub

End If

End If

If zt = 1 Then

js = js + 1

n = 10 - js

Call xsjtd("黄", n)

If js >= 10 Then

zt = 2

js = 0

Exit Sub

End If

End If

If zt = 2 Then

js = js + 1

n = 30 - js

Call xsjtd("绿", n)

If js >= 30 Then

zt = 0

js = 0

Exit Sub

End If

End If

End Sub

从图上看是在三个窗体里，
不过这也很简单，你可以用，
public 定义全局变量来处理
倒计时变量。

考察timer的用法，这个有啥难度？