unity2dでフェードアウトフェードインを作りたい

**Unityで始めるc＃**という本を読みながら脱出ゲームを作っています。

c＃
1using System.Collections;
2using System.Collections.Generic;
3using UnityEngine;
4using UnityEngine.SceneManagement;
5using UnityEngine.UI;
6
7public class GameManeger : MonoBehaviour {
8    public const int WALL_1 = 1;
9    public const int WALL_2 = 2;
10    public const int WALL_3 = 3;
11    public const int WALL_4 = 4;
12    public const int WALL_5 = 5;
13    public const int WALL_6 = 6;
14    public const int WALL_7 = 7;
15    public const int WALL_8 = 8;
16    public const int WALL_9 = 9;
17    public const int WALL_10 = 10;
18    public const int WALL_11 = 11;
19
20    public GameObject panelWalls;
21
22    private int wallNo;
23
24    // Use this for initialization
25    void Start () {
26        wallNo = WALL_1;
27	}
28	
29	// Update is called once per frame
30	void Update () {
31		
32	}
33
34    public void PushButtonRight(){
35        wallNo++;
36        if (wallNo > WALL_11){
37            wallNo = 1;
38        }
39        DisplayWall();
40    }
41
42    void DisplayWall(){
43        switch (wallNo) {
44            case WALL_1:
45                panelWalls.transform.localPosition = new Vector3(0.0f, 0.0f, 0.0f);
46                break;
47
48            case WALL_2:
49                panelWalls.transform.localPosition = new Vector3(-2000.0f, 0.0f, 0.0f);
50                break;
51
52            case WALL_3:
53                panelWalls.transform.localPosition = new Vector3(-4000.0f, 0.0f, 0.0f);
54                break;
55
56            case WALL_4:
57                panelWalls.transform.localPosition = new Vector3(-6000.0f, 0.0f, 0.0f);
58                break;
59
60            case WALL_5:
61                panelWalls.transform.localPosition = new Vector3(-8000.0f, 0.0f, 0.0f);
62                break;
63
64            case WALL_6:
65                panelWalls.transform.localPosition = new Vector3(-10000.0f, 0.0f, 0.0f);
66                break;
67
68            case WALL_7:
69                panelWalls.transform.localPosition = new Vector3(-12000.0f, 0.0f, 0.0f);
70                break;
71
72            case WALL_8:
73                panelWalls.transform.localPosition = new Vector3(-14000.0f, 0.0f, 0.0f);
74                break;
75
76            case WALL_9:
77                panelWalls.transform.localPosition = new Vector3(-16000.0f, 0.0f, 0.0f);
78                break;
79
80            case WALL_10:
81                panelWalls.transform.localPosition = new Vector3(-18000.0f, 0.0f, 0.0f);
82                break;
83
84            case WALL_11:
85                panelWalls.transform.localPosition = new Vector3(-20000.0f, 0.0f, 0.0f);
86                break;
87        }
88    }
89}
90