int a = 2;
int b = 3;
int c = 4;
int d = 5;
int e = 6;
int f = 7;
int g = 8;

int pins[] = {a, b, c, d, e, f, g};

int O[] = {1, 1, 1, 1, 1, 1, 0};
int H[] = {0, 1, 1, 0, 1, 1, 1};
int Pe[] = {1, 1, 1, 0, 1, 1, 0};
int one[] = {0, 1, 1, 0, 0, 0, 0};
int four[] = {0, 1, 1, 0, 0, 1, 1};
int five[] = {1, 0, 1, 1, 0, 1, 1};

int* symbols[] = {O, H, Pe, one, four, five};
int symbolCount = 6;

void setup() {
  for (int i = 0; i < sizeof(pins)/sizeof(pins[0]); i++) {
    pinMode(pins[i], OUTPUT);
    digitalWrite(pins[i], HIGH);
  }
}

int i = 0;

void loop() {
  out(symbols[i], sizeof(pins)/sizeof(pins[0]));
  i++;
  delay(1000);
  if (i == symbolCount) {
    i = 0;
  }
}

void out(int symbol[], int size) {
  for (int i = 0; i < size; i++) {
    if (symbol[i] == 1) {
      digitalWrite(pins[i], LOW);
    }
    else {
      digitalWrite(pins[i], HIGH);
    }
  }
}