[BEGINNER] Generating Terrain with Perlin noise flat and nothing happens ?

Hi

the Script below should make a cube, and then copy it while setting the depth according to the perlin noise, and always go +1 along both z and x axis. However, when I run the script, the cubes are all on the same heigth.

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class terrainGen : MonoBehaviour { public terrainGen terrain; private GameObject cube; private int seed = 4864842; private float heigth;

  // Use this for initialization
  void Start () {
      cube = GameObject.CreatePrimitive(PrimitiveType.Cube);
      editTerrain ();
      heigth = 0.0f;
  }
 
  void editTerrain()
  {
      int xResolution = 50;
      int zResolution = 50;
      //float[,] heights;
 
      for(int z=0; z <= zResolution ; z++)
      {
          for(int x=0; x <= xResolution ; x++)
          {
              float y = Mathf.PerlinNoise (heigth+seed, 0.0f);
              Debug.Log (heigth);
              heigth = heigth + 100f;
              Instantiate(cube, new Vector3(x, y, z),Quaternion.identity);
          }
      }
  }
 

}