Load default quad mesh from resources

It seems that the shortest way to do this is to write a script that generates a quad from scratch. Here is a script that I found:

 using System;
 using UnityEngine;
 using UnityEditor;
 
 public class CreateQuadMesh : Editor {
   
     [MenuItem("Assets/Create/Quad Mesh", false, 10000)]
     public static void Create ()
     {
         Mesh mesh = BuildQuad (1, 1);
         string name = "Quad Mesh";
         mesh.name = name;
         AssetDatabase.CreateAsset (mesh, String.Format ("Assets/{0}.asset", name));
         EditorUtility.FocusProjectWindow ();
         Selection.activeObject = mesh;
     }
     
     private static Mesh BuildQuad (float width, float height)
     {
         Mesh mesh = new Mesh ();
         
         // Setup vertices
         Vector3[] newVertices = new Vector3[4];
         float halfHeight = height * 0.5f;
         float halfWidth = width * 0.5f;
         newVertices [0] = new Vector3 (-halfWidth, -halfHeight, 0);
         newVertices [1] = new Vector3 (-halfWidth, halfHeight, 0);
         newVertices [2] = new Vector3 (halfWidth, -halfHeight, 0);
         newVertices [3] = new Vector3 (halfWidth, halfHeight, 0);
         
         // Setup UVs
         Vector2[] newUVs = new Vector2[newVertices.Length];
         newUVs [0] = new Vector2 (0, 0);
         newUVs [1] = new Vector2 (0, 1);
         newUVs [2] = new Vector2 (1, 0);
         newUVs [3] = new Vector2 (1, 1);
         
         // Setup triangles
         int[] newTriangles = new int[] { 0, 1, 2, 3, 2, 1 };
         
         // Setup normals
         Vector3[] newNormals = new Vector3[newVertices.Length];
         for (int i = 0; i < newNormals.Length; i++) {
             newNormals [i] = Vector3.forward;
         }
         
         // Create quad
         mesh.vertices = newVertices;
         mesh.uv = newUVs;
         mesh.triangles = newTriangles;
         mesh.normals = newNormals;
         
         return mesh;
     }
 }