pulsing LED – fireflies on an Espruino

Just a bit of magic and you have a nice collection of fireflies on an Espruino:

function createFireFly(milliseconds) {
  milliseconds = ((typeof milliseconds) === "undefined") ? 0 : milliseconds;
  setTimeout(function() {
    var led;
    var next = Math.random();
    if (next <= 0.05) {
      led = LED1;
    } else if (next <= 0.1) {
      led = LED3;
    } else {
      led = LED2;
    }
    var duration = 1000 + Math.random() * 2000;
    led.glow(duration);
    createFireFly(duration);
  // activate the new firefly after the current one is done, 
  // with an added delay of at most 1 second
  // though every so often ... it may take a bit longer
  }, milliseconds + Math.random() * 2000 + (Math.random() < 0.01 ? 5000 + Math.random() * 10000 : 0 ));
}