I'm afraid pictures just wouldn't do this justice, so here's a video instead of one complete cycle
As you can see from the video, the oscillators of the 2 LEDs aren't matched exactly, but I think it actually makes it more interesting.
[UPDATE] The LEDs I bought (in Australia) are from Jayacar. Link to the LEDs on their site:
Some people have found them at All Electronics (I think that's in the US). Link to the LEDs on their site:
Nachonut has started selling similar LEDs. His LEDs flash, as opposed to fade. Check his thread:
Edited by dzv, 24 June 2003 - 03:24 AM.