const int loopDelay     = 100;                        // Sets the overall loop speed in uS (higher is slower)

const int randMin       = 0;                          // minimum and maximum star brightness
const int randMax       = 255;

const  long odds        = 2999;                       // Odds to beat or we stay off
const long coinTosses   = 3000;                       // Out of
long didIGetLucky;                                    //

const int stars         = 6;                          // Number of LEDs ("stars")
int star[]              = {3, 5, 6, 9, 10, 11};       // Pin assignments of "stars"
int si                  = 0;                          // Star Index - ie Current "star" we're working with
int starBright[stars];                                // "Star" brightness
int starTarget[stars];                                // "Star" target brightness

void setup() 
{
 for (si = 0; si < stars; si++)
  {
    pinMode(star[si], OUTPUT);
  }
}

void loop() 
{
  for (si = 0; si < stars; si++)                      // Loop for as many times as there are "stars"
  {
    if (starBright[si] == starTarget[si])             // If we've reached the previously set target then we need to set a new target
    {
      starTarget[si] = random(randMin, randMax);      //Set new target brightness

      didIGetLucky = random(coinTosses);              // Did I beat the odds?
      if (didIGetLucky < odds)                        // Usually not - so ...
      {
        starTarget[si] = 1;                           // Set a target of almost nothing (so it still gets something to do)
        starBright[si] = 0;                           // Set current brightness to off
      }
    }

    if (starBright[si] != starTarget[si])             // If star brightness change required then ...
    {
      if (starBright[si] < starTarget[si])            // Do this if we need to increase star brightness
      {
        analogWrite(star[si], starBright[si]);        // Make the change
        starBright[si]++;                             // Increase star brightness for next time
      }

      if (starBright[si] > starTarget[si])            // Do this if we need to decrease star brightness
      {
        analogWrite(star[si], starBright[si]);        // Make the change
        starBright[si]--;                             // Decrease star brightness for next time
      }
    }

    delayMicroseconds(loopDelay);                     // Sets overall loop speed
  
  }
}