Two solutions come to mind: opamps and pics.

I recently wrote a little program for the 10F206 to generate 3 pwm 
outputs to 3 leds.  They slowly pulsate at different rates and will go 
into some garden path lanterns.  A fourth input pin will use a CdS 
photocell to turn it on/off at night/day.

As for opamps, consider a state-variable oscillator.  These have two 
integrators in series followed by an inverter that goes back around to 
the input.  The 2 integrators give 'normal' and 'quadrature' (ie zero 
and 90 degrees) phased sine waves.  Running each of these through linear 
inverters produces four outputs: 0, 90, 180, and 270 degrees which 
sounds a lot like what you might be looking for.  Details abound on the 
net; for a dead-tree reference, check out Horowitz & Hill.

Good luck!
MD

Ed Edmondson wrote:
> My wife is making a ceramic light house for a Christmas gift for her 
> mother. You know, the mother-in-law thing. I was wondering about 
> installing a red and white LED pair in the tower to simulate the tower 
> beam. I was thinking of slowly fading the front white LED and rear red 
> LED and then reversing to the second pair of LED's with the white in the 
> rear red in the front. Then the cycle repeats itself again.
> 
> Any suggestions on this and how to simply implement the circuitry?
> 
> Thanks,
> Ed

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