int baseLed = 2;
int numLed = 5;
int delayTime=100;
int bPinA = 11;
int bPinB = 12;

void setup() {
  for (int i=0; i<numLed; i++){
    pinMode(baseLed+i, OUTPUT);
    digitalWrite(baseLed+i, LOW);
  }
  pinMode(bPinA, INPUT);
  pinMode(bPinB, INPUT);
}

void cycle(int delayTime) {
  for(int i=0; i<numLed; i++){
    digitalWrite(baseLed+i, HIGH);
    delayTime = changeDelay ();
    delay(delayTime);
    digitalWrite(baseLed+i, LOW);
  }
}

int changeDelay() {
  if (digitalRead(bPinA)) {
    delayTime = delayTime + 10;
  }
  if (digitalRead(bPinB)) {
    delayTime = delayTime - 10;
  }
  if (delayTime > 1000) {
    delayTime = 1000;
  }
  if (delayTime < 10) {
    delayTime = 10;
  }
  return delayTime;
}

void loop() {
  cycle(8);
  }