How make random mc without array ? as3

this my code : :q:
import flash.utils.Timer;
import flash.events.TimerEvent;

var num_count:Number=0;
var txt_score: TextField = new TextField();
var merah:Merah = new Merah;
var hijau:Hijau = new Hijau;
var kuning:Kuning = new Kuning;
var array:Array = [merah, kuning, hijau];
var timer:Timer = new Timer(3000, 9);
var count:Number = 1;
var border:Border = new Border;

addChild (txt_score);
txt_score. text = “0”;
txt_score. height = 20;
txt_score. border = true;
txt_score. y=20;
txt_score. x=450;

addChild(border);
border.x = 150;
border.y = 38.5;

timer.addEventListener(TimerEvent.TIMER, trafficControl);
function trafficControl(event:TimerEvent):void
{
if (count == 4)
{
count = 1;
}

switch (count) 
{ 
    case 1: 
        merah.visible= true; 
		addChild(merah);
		merah.x = 116.5;
		merah.y = 43.5;
		kuning.visible = false; 
        hijau.visible = false; 
        break; 
    case 2: 
        merah.visible = false; 
        kuning.visible = true; 
		addChild(kuning);
		kuning.x = 176.5;
		kuning.y = 43.5;
        hijau.visible = false; 
        break; 
    case 3: 
        merah.visible = false; 
        kuning.visible = false; 
        hijau.visible = true; 
		addChild(hijau);
		hijau.x = 236.5;
		hijau.y = 43.5;
        break; 
} 
 
count++; 

}

timer.start();

gas.addEventListener(MouseEvent.CLICK, jalan, false, 0, true);
function jalan(event:MouseEvent):void
{

hijau.visible = false;
kuning.visible = false;
merah.visible = false;

if (count == 4){
txt_score. text = String (++num_count);
} else if (count == 3){

}  else if (count == 2){

}

}
rem.addEventListener(MouseEvent.CLICK, mandek, false, 0, true);
function mandek(event:MouseEvent):void
{
if (count == 2){
txt_score. text = String (++num_count);
} else if (count == 4){

}  else if (count == 3){

}
merah.visible = false;
kuning.visible = false;
hijau.visible = false;

}

kopling.addEventListener(MouseEvent.CLICK, setengah, false, 0, true);
function setengah(event:MouseEvent):void
{
kuning.visible = false;
hijau.visible = false;
merah.visible = false;

if (count == 3){
txt_score. text = String (++num_count);
} else if (count == 4){

}  else if (count == 2){

}

}

help please…