Spawn Object

Hello im trying to spawn wall, i have start point and end point, i drag mouse this white mini wall and when i stop holding mouse button it should spawn wall object on left. When i make long mini wall i need to spawn more wall prefabs in road. But my code works bad, any advice ?

 void VytvorStenu(){
         float distance = Vector3.Distance (start.transform.position, end.transform.position);
         if (!creating) {
             Vector3 pozicia = start.transform.position;
             //float distance = Vector3(start.transform.position, end.transform.position);
             for(float x = 17; x < distance; x+=17){
             plocik = (GameObject)Instantiate (plot, pozicia, Quaternion.identity);
                 plocik.transform.LookAt (end.transform.position);
             pozicia = start.transform.position + new Vector3(17f,0,0);
                 Destroy (stena);}
             Destroy(stena);
         }
     }