点击地面时，若鼠标点击的偶数次使得Cube向点击点移动，并且点击奇数次Cube变色

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

public class ray10 : MonoBehaviour
{
    int num = ;
    Vector3 vec;
    GameObject obj;
    bool b = false;
    Color[] a = { Color.blue, Color.cyan, Color.gray, Color.green, Color.red, Color.yellow };

    // Use this for initialization
    void Start()
    {
        //GameObject obj = GameObject.CreatePrimitive(PrimitiveType.Cube);
        //obj.transform.position = Vector3.zero;//one表示坐标（1，1，1）
        //obj.transform.localScale = new Vector3(1, 1, 1);//大小设置
    }

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

        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit))
        {
            if (Input.GetMouseButtonDown())
            {
                vec = hit.point;
                num++;

                if (num %  == )//偶数次
                {
                    transform.LookAt(new Vector3(vec.x, vec.y + 0.5f, vec.z));
                    b = true;
                }
                if(num%!=)
                {
                    GetComponent<MeshRenderer>().material.color = a[Random.Range(, a.Length)];

                }
            }

        }
            if (b)
            {
              transform.Translate(, ,  * Time.deltaTime);
                if (Vector3.Distance(transform.position, new Vector3(vec.x, vec.y + 0.5f, vec.z)) < 0.1f)
                {
                    b = false;

                }
            }
    }
}