I decided to play a little bit with batteries and LEDs to make an animated smoke marker. To make the marker I used CR1620 battery and two pulsing LEDs - red and yellow.
Below you can see a simple prototype I made, however, there are couple of things to improve. Unfortunately, yellow diode does not shine as bright as the red one. I had also a problem with the switch (actually, in the movie you see below, the yellow diode didn't turn on).