struct {
  const unsigned long duration;
  const int value;
} sequence[] = {
  {600, 0},
  {400, 2},
  {600, 1},
  {400, 2},
};

const size_t sequenceCount = sizeof sequence / sizeof * sequence;

unsigned long lastChange;
size_t currentSequence = 0;

void tick() {
  if (millis() - lastChange >= sequence[currentSequence].duration) {
    Serial.println(sequence[currentSequence].value);
    currentSequence = (currentSequence + 1) ;
    if (currentSequence >= sequenceCount) {
      currentSequence = 0;
      Serial.println(F("-----"));
    }
    lastChange = millis();
  }
}

void setup() {
  Serial.begin(115200); Serial.println();
  lastChange = millis();
}

void loop() {
  tick();
}