#define TRUE 1
#define FALSE 0
const int numLEDs = 4;
const int GPIO_Pins[] = {2,3,4,5};
const int runRate = 200;
static bool direction = TRUE;
void setup() {
  // put your setup code here, to run once:
  for (int led = 0; led < numLEDs; led++)
  {
    pinMode(GPIO_Pins[led], OUTPUT);
  }
}
void loop() {
  // put your main code here, to run repeatedly:
  runningLEDs(runRate, direction);
  direction = !direction;

}
void runningLEDs(int runRate, bool direction)
{
  if(direction == TRUE) {
  for (int led = 0; led < numLEDs; led++)
  {
    digitalWrite(GPIO_Pins[led], HIGH);
    delay(runRate);
    digitalWrite(GPIO_Pins[led], LOW);
    //delay(runRate);
  }
}
else {
  for (int led = numLEDs-1; led >= 0; led--)
  {
    digitalWrite(GPIO_Pins[led], HIGH);
    delay(runRate);
    digitalWrite(GPIO_Pins[led], LOW);
    //delay(runRate);
  }
}
}