A long time ago I wrote an IEnumerable to create a Fibonacci series - but lost it. Now I came up with this:

static IEnumerable<double> FibonacciSeries(int count)
        {
            double x = 0;
            double y = 1;
            for (int i = 0; i < count/2; i++)
            {
                yield return x = x + y;
                yield return y = x + y;
            }
        }

but I've a feeling that the old, lost, version was more concise. Anyone see a way of improving the above ?