Adding a Flyweight factory

In the Scripts folder, create a new C# script named FlyweightFactory and update its contents to match the following code block, which stores a Dictionary of IFlyweight objects (indexed by the TerrainType name) and returns either a newly created or reused tile flyweight when queried by the client:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
// 1
public class FlyweightFactory
{
    // 2
    private static Dictionary<string, IFlyweight> _cache = new Dictionary<string, IFlyweight>();
    // 3
    public static IFlyweight GetFlyweight(TerrainType type)
    {
        // 4
        var key = type.ToString();
        // 5
        if(!_cache.ContainsKey(key))
        {
            IFlyweight newTile = null;
            switch(type)
            {
                case TerrainType.Ground:
                    newTile = new Tile(type, Color.white, 0.75f);
                    break;
                case TerrainType.Water...