uint32_t ms = 1000;

uint8_t pin[] = {
  11, 2, 3, 4, 5, 6, 7, 8, 9, 10
};

void setDelayTime(){
  static uint8_t itr = 2;
  static bool down = true;

  uint32_t times[] = { 100, 250, 500, 1000 };

  ms = times[itr];

  if(down){
    itr--;
    if(itr == 0) down = false;
  }
  else{
    itr++;
    if(itr == 3) down = true;
  }
}

void setup() {
  for (uint8_t led = 0; led < 10; ++led) {
    pinMode(pin[led], OUTPUT);
  }
}

void loop() {
  int8_t led = 9;

  digitalWrite(pin[led], HIGH);
  delay(ms);

  for(led = 8; led >= 0; --led){
    digitalWrite(pin[led + 1], LOW);
    digitalWrite(pin[led], HIGH);

    delay(ms);
  }

  setDelayTime();

  for(led = 1; led < 9; ++led){
    digitalWrite(pin[led - 1], LOW);
    digitalWrite(pin[led], HIGH);

    delay(ms);
  }

  digitalWrite(pin[led - 1], LOW);
  digitalWrite(pin[led], LOW);

  setDelayTime();

}