Flashing Joule Thief

I have been looking for a Joule Thief circuit that works nicely with my cement batteries,and finally found one.It is called the Simplified Flashing Joule Thief ,and that is exactly what it does.
Here is the link to the page:Quantsuff's LED Page.

I will make a few of these circuits,with slight differences between them.The first one has a red LED and four capacitors with two on-off-on switches,so I can change the flashing rate.The next one will have a potentio meter.