unity editor stck if i give a value greater than 0 to my time variable.whats the problem?

using UnityEngine;
using System.Collections;
public class Spawner : MonoBehaviour {
public GameObject fallingBlockPrefab;

public float timeLeft;
public float secondsBetweenSpawns = 1;
float nextSpawnTime;
public Vector2 spawnSizeMinMax;
public float spawnAngleMax;
Vector2 screenHalfSizeWorldUnits;
// Use this for initialization
void Start () {
	screenHalfSizeWorldUnits = new Vector2 (Camera.main.aspect * Camera.main.orthographicSize, Camera.main.orthographicSize);
}
void FixedUpdate ()
{
	timeLeft -= Time .deltaTime;

}

// Update is called once per frame
void Update ()

{

	while (timeLeft  >0)
	{
		if (Time.time > nextSpawnTime) 
		{
			nextSpawnTime = Time.time + secondsBetweenSpawns;
			float spawnAngle = Random.Range (-spawnAngleMax, spawnAngleMax);
			float spawnSize = Random.Range (spawnSizeMinMax.x, spawnSizeMinMax.y);
			Vector2 spawnPosition = new Vector2 (Random.Range (-screenHalfSizeWorldUnits.x, screenHalfSizeWorldUnits.x), screenHalfSizeWorldUnits.y + spawnSize / 0.2f);
			GameObject newBlock = (GameObject)Instantiate (fallingBlockPrefab, spawnPosition, Quaternion.Euler (Vector3.forward * spawnAngle));
			newBlock.transform.localScale = Vector2.one * spawnSize;
		}
	}
	
}

}

timeLeft -= Time .deltaTime;

  1. there is a space between Time and dot.

  2. there are easier way to do what you do instead of this weird combination of FixedUpdate and Update, he is some example:

      public float spawnInterval = 1; // 1 second
    public bool autoStartSpawn = true;
     
     void Start () {
         if (autoStartSpawn)
             StartSpawning();
     }
     
     [ContextMenu("Start Spwning")]
     void StartSpawning()
     {
         InvokeRepeating("Spawn", 0, spawnInterval);
     }
    
     [ContextMenu("Stop Spawning")]
     void StopSpawning()
     {
         CancelInvoke("Spawn");
     } 
    
     void Spawn()
     {
         Debug.Log("Spawned");
     }