How Does Slider Work ?

[ata]

Hi everybody   The following does not work properly.Could you please help me understand the slider logic?

Code:

x[1]= Shapes.AddText(1)
Shapes.Zoom(x[1],7,7)
Shapes.Move(x[1],600,120)
For i= 2 To 12
  x[i]= Shapes.AddText(i)
  Shapes.Zoom(x[i],7,7)
  y= Shapes.GetTop(x[i-1])
  Shapes.Move(x[i],600,y+105)
  y= Shapes.GetTop(x[i])
EndFor

LDControls.SliderMaximum= 2
Slider= LDControls.AddSlider(40,600,"V")
Shapes.Move(slider,500,100)
t= LDControls.SliderGetValue(slider)
Stack.PushValue("t",t)
LDControls.SliderChanged= change

Sub change
  t= Stack.PopValue("t")
  z= LDControls.SliderGetValue(slider) 
    If z>t Or z=t Then
      For i= 1 To 12
        Shapes.Move(x[i],600,Shapes.GetTop(x[i])-2)
      EndFor
      v= LDControls.SliderGetValue(Slider)
      Stack.PushValue("t",v)
    ElseIf z<t then
      For i= 1 To 12
        Shapes.Move(x[i],600,Shapes.GetTop(x[i])+2)
      EndFor
      v= LDControls.SliderGetValue(Slider)
      Stack.PushValue("t",v)
  EndIf
EndSub