platforms spawning towards my player

hello guys firstly i am very sorry if my question is dump. i am newbie. i am creating a 2d game like doodlejump. I spawn platforms randomly but somewhere platforms spawn towards my player. here is a photo: http://imgur.com/a/PLYCn Here is my code:

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 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 
 public class GameManager : MonoBehaviour {
     public Transform player; //obj to track is player
     float playerHeightY; // height at which camera will adjust to
 //defining platform prefabs
 public Transform step;
 public Transform upDown;
 public Transform doubleJump;
 public Transform justStep;

 private float platformNum; //number of selected platform
 private float platformCheck;
 private float spawnPlatformsTo;


 void Start () {
     player = GameObject.FindGameObjectWithTag ("Player").transform;
     PlatformSpanner(-2.0f); //seed of randomizing
     }
 
 
 void Update () {
     playerHeightY = player.position.y;
             if (playerHeightY > platformCheck) {

     PlatformManager ();
     }

}

 void PlatformManager() {
     platformCheck = player.position.y + 15;
     PlatformSpanner (platformCheck + 15);
 }

 void PlatformSpanner(float floatValue){
 float y = spawnPlatformsTo;
           while(y <= floatValue){
         float x = Random.Range (-2.35f, 2.35f);
         platformNum = Random.Range(0f,.9f); //which one of prefabs
         Vector2 posXY = new Vector2(x,y);//position of prefabs

         if (platformNum > 0.8) {
             Instantiate (upDown, posXY, Quaternion.identity);
         }

         else if (platformNum > 0.9) {
             Instantiate (doubleJump, posXY, Quaternion.identity);
         }

         else if (platformNum > 0.7) {    
             //object, position, identitiy
             Instantiate (step, posXY, Quaternion.identity);
         }
         else if (platformNum > 0.5) {
             //instantiating prefabs at runtime
             Instantiate (justStep, posXY, Quaternion.identity);
         } 
         y += Random.Range (0.5f,1.5f);
 }
     spawnPlatformsTo = floatValue;
 }

}