using System;
using System.Linq;
using System.Collections.Generic;

public static class Test
{
    public static IEnumerable<T> Last<T>(this IEnumerable<T> source, int n)
    {
        using(var it = source.GetEnumerator())
        {
    	    var buffer = new T[n];
    	    var i = 0;

            while (it.MoveNext())
        	    buffer[(i++) % n] = it.Current;
            
            var len = Math.Min(n, i);
            for (int j = i - len; j < i; j++)
           		yield return buffer[ (j + n) % n]; 

        }
    }

	public static void Main()
	{
		var seq = new[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
		foreach (var n in seq.Last(5))
		    Console.Write(string.Format("{0} ", n));
	}
}