int colAnodes[] = {23, 25, 27};
int rowCathodes[] = {29, 39, 51};
unsigned long nextCharTime = millis() + 500;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);

  Serial.println(sizeof(colAnodes) / sizeof(colAnodes[0]));
  for (int pointer = 0; pointer <= 2; pointer ++) {
    pinMode(colAnodes[pointer], OUTPUT);
    digitalWrite(colAnodes[pointer], LOW);
  }
  Serial.println (sizeof(rowCathodes) / sizeof(rowCathodes[0]));
  for (int pointer = 0; pointer <= 2; pointer ++) {
    pinMode(rowCathodes[pointer], OUTPUT);
    digitalWrite(rowCathodes[pointer], HIGH);
  }

}

void loop() {
  // put your main code here, to run repeatedly:
  if (millis() < nextCharTime){
  lightLED(0, 0);
  lightLED(0, 1);
  lightLED(0, 2);
  lightLED(1, 0);
  lightLED(1, 2);
  lightLED(2, 0);
  lightLED(2, 1);
  lightLED(2, 2);
  } else{
    nextCharTime = millis() + 500;
  }
  if (millis() < nextCharTime){
  lightLED(0, 0);
  lightLED(1, 1);
  lightLED(2, 0);
  lightLED(0, 2);
  lightLED(2, 2);
  } else{ 
    nextCharTime = millis() + 500;
  }

void lightLED(int col, int row) {
  for (int pointer = 0; pointer <= (sizeof(colAnodes) / sizeof(colAnodes[0])) - 1; pointer ++) {
    pinMode(rowCathodes[pointer], OUTPUT);
    digitalWrite(rowCathodes[pointer], HIGH);
  }
  for (int pointer = 0; pointer <= (sizeof(colAnodes) / sizeof(colAnodes[0])) - 1; pointer ++) {
    pinMode(colAnodes[pointer], OUTPUT);
    digitalWrite(colAnodes[pointer], LOW);
  }
  digitalWrite(colAnodes[col], HIGH);
  digitalWrite(rowCathodes[row], LOW);

}