Swapping values randomly every 2 seconds.

Hello!

I'm trying to create a script that swap a value every two seconds, and it randomly chooses the values between 1 and 0;

My issue is that it only swaps it once. and not continuously (and not even randomly).

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class talknWalkSwap : MonoBehaviour
 {
     int swap;
 
 
     // Start is called before the first frame update
     void Start()
     {
         StartCoroutine(ChangeTag());
         Debug.Log(swap);
     }
 
     // Update is called once per frame
     void Update()
     {
     }
 
 
 
     IEnumerator ChangeTag()
     {
         var wait = new WaitForSeconds(3);
         while (true)
         {
             yield return wait;
             swap = 1;
             yield return wait;
             swap = 0;
         }
     }
 
 }