I think the circuit is a fascinating exploration into a number of interesting concepts. All well worth the cost in parts and time for the newbie and the oldie. And you get a neat little fading LED module in the bargain. WIN, WIN, WIN!!!!/hijack mode on/
The basic idea of the dual oscillator is definately going to make it the 555 projects. It is an excellent way to introduce someone to the concept of hetrodyne, as well as being interesting visually. It could be one of the better ideas I've had. You'll note the diode bridge strongly resembles a balanced modulator.
/hijack mode off/
hgmjr