unity C#生成楼梯

using UnityEngine;
using System.Collections;

public class LouTi : MonoBehaviour {
    public GameObject cube;
    private float angle = 15;
	// Use this for initialization
	void Start () {
        for (int i = 0; i < 30; i++)
        {
            float hudu = (angle / 180) * Mathf.PI;
            GameObject ccc = (GameObject)Instantiate(cube);
            if (i<10)
            {
               
                ccc.transform.position = new Vector3(-10 + i, (-10 + i)*Mathf.Tan(hudu), 0);    
            }
            else if (i>=10&&i<=21)
            {
                ccc.transform.position = new Vector3(-10 + i, -(-10 + i) * Mathf.Tan(hudu), 0);      
            }
            else 
            {
                ccc.transform.position = new Vector3(-10 + i, -(-10 + 21) * Mathf.Tan(hudu), 0); 
            }
        }
	}
	
	// Update is called once per frame
	void Update () {
	
	}
}