Scripted Plane not visible

So I wanted to code a simple plane with this code:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class PlaneCreation : MonoBehaviour {
5.  
6.     // Use this for initialization
7.     void Start () {
8.  
9.  
10.     MeshFilter mf = GetComponent<MeshFilter>();
11.     Mesh mesh = new Mesh();
12.     mf.mesh = mesh;
13.  
14.  
15.  
16.         Vector3[] wv = new Vector3[4];
17.  
18.         wv[0] = new Vector3(-2,0,0);
19.         wv[1] = new Vector3(-2,4,0);
20.         wv[2] = new Vector3(2,0,0);
21.         wv[3] = new Vector3(2,4,0);
22.  
23.         mesh.vertices = wv;
24.  
25.  
26.         int[] tri = new int[6];
27.  
28.         tri[0] = 0;
29.         tri[0] = 1;
30.         tri[0] = 2;
31.  
32.         tri[0] = 1;
33.         tri[0] = 3;
34.         tri[0] = 2;
35.  
36.         mesh.triangles = tri;
37.  
38.  
39.         Vector3[] normals = new Vector3[4];
40.  
41.         normals[0] = -Vector3.forward;
42.         normals[1] = -Vector3.forward;
43.         normals[2] = -Vector3.forward;
44.         normals[3] = -Vector3.forward;
45.  
46.         mesh.normals = normals;
47.  
48.  
49.         Vector2[] uv = new Vector2[4];
50.  
51.         uv[0] = new Vector2(0,0);
52.         uv[0] = new Vector2(1,0);
53.         uv[0] = new Vector2(0,1);
54.         uv[0] = new Vector2(1,1);
55.  
56.         mesh.uv = uv;
57.  
58.     }
59.    
60.     // Update is called once per frame
61.     void Update () {
62.    
63.     }
64. }
65.  

But the plane is not visible. I already tried flipping the normals and/or rotating the empty game Object but that did nothing.
Here is the empty game Object the script is attached too.
And here a screen shot of my camera in case something is wrong there.

Any idea how to fix this?

 

Between line 28 and 35, you only change the first element of the triangle indices.

 

Now I feel realy dumb. But thanks a lot!