public class Material
	{
		public class ElementsCollection
		{
			private ArrayList els = new ArrayList();

			public Element this[int index]
			{
				get
				{
					if (index < 0 || index >= this.els.Count)
						throw new IndexOutOfRangeException("Index out of range.");
					return (Element)els[index];
				}
			}
			public Element this[string name]
			{
				get
				{
					foreach (object el in els)
					{
						if (((Element)el).Name == name)
							return (Element)el;
					}
					throw new ArgumentException("Incorrect argument");
				}
			}

			public int Count { get { return els.Count; } }

			#region Methods
			public int Add(object newObj)
			{
				return els.Add(newObj);
			}
			public void AddRange(object[] newObjs)
			{
				foreach (object var in newObjs)
					this.Add(var);
			}			#endregion
		}

		private ElementsCollection collection = new ElementsCollection();

		#region .ctor
		public Material(params Element[] elements)
		{
			collection.AddRange(elements);
		}
		#endregion

		public ElementsCollection Element
		{
			get { return this.collection; }
		}
		public int CountOfElements
		{
			get { return collection.Count; }
		}
	}