#define ROW1 11  //red
#define ROW2 12  //green
#define ROW3 13  //blue

#define REFRESH 100u
#define INTERVAL 500u

void setup() {
  // put your setup code here, to run once:
  for (unsigned char i = 2; i <= ROW3; ++i)
    pinMode(i, OUTPUT);
  digitalWrite(ROW2, true);
  digitalWrite(ROW3, true);
}

unsigned char c{};
unsigned long iTimestamp{}, rTimestamp{};
bool on = true, direction = 0; // 0 - forward, 1 - backward

void loop() {
  // put your main code here, to run repeatedly:
  if (millis() >= rTimestamp) {
    digitalWrite(c % 9 + 2, !direction);
    for (unsigned char i = c % 9 + 1; i <= 9 + c / 9; ++i)
      if (i >= 9)
        digitalWrite(i + 2, !on);
      else
        digitalWrite(i + 2, on && i < c);
    rTimestamp = millis() + REFRESH;
    on = !on;
  }
  if (millis() >= iTimestamp) {
    c = (c + 1 - 2 * direction) % 27;
    iTimestamp = millis() + INTERVAL;
  }
}


//      digitalWrite(i + 2, on && !(i - 9 < c / 9 && i >= 9));