An infinite sequence repeating another sequence.

BrokenRecord.cs

public class BrokenRecord<T> : IEnumerable<T>
{
  private readonly IEnumerable<T> _seq;

  public BrokenRecord(IEnumerable<T> seq)
  {
    _seq = seq;
  }

  public IEnumerator<T> GetEnumerator()
  {
    var e = _seq.GetEnumerator();
    return new BrokenRecordEnumerator<T>(e);
  }

  IEnumerator IEnumerable.GetEnumerator()
  {
    return GetEnumerator();
  }
}

public class BrokenRecordEnumerator<T> : IEnumerator<T>
{
  private readonly IEnumerator<T> _seq;

  public BrokenRecordEnumerator(IEnumerator<T> seq)
  {
    _seq = seq;
  }

  public void Dispose() {}

  private bool ResetAndMoveNext()
  {
    Reset();
    return _seq.MoveNext();
  }

  public bool MoveNext()
  {
    return _seq.MoveNext() || ResetAndMoveNext();
  }

  public void Reset()
  {
    _seq.Reset();
  }

  public T Current
  {
    get
    {
      return _seq.Current;
    }
  }

  object IEnumerator.Current
  {
    get { return Current; }
  }
}