Two-digit counter on an Arduino Uno

// Two-digit counter: a bare two-digit display, multiplexed by the sketch.
//
//   segments A B C D E F G DP -> pins 2 to 9, each through its own 220 ohm
//   digits DIG1 and DIG2      -> pins 10 and 11
//
// Ten legs for two digits: each segment leg goes to that segment in both
// digits, and each digit has one common leg, so only one digit can be lit at
// a time. The sketch shows them in turn, five milliseconds each, and the eye
// sees both at once, each half as bright.
//
// Common cathode: a digit is selected by pulling its common LOW, and a
// segment lit by driving its leg HIGH.

const uint8_t SEGMENT_PINS[8] = {2, 3, 4, 5, 6, 7, 8, 9};
const uint8_t DIGIT_PINS[2] = {10, 11};

// Bit 0 is segment A, bit 6 is G, bit 7 the point.
const uint8_t FONT[10] = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F};

int count = 0;
unsigned long lastCount = 0;

void showDigit(uint8_t which, uint8_t pattern) {
  for (uint8_t i = 0; i < 2; i++) digitalWrite(DIGIT_PINS[i], HIGH);  // all off first: no ghost
  for (uint8_t s = 0; s < 8; s++) digitalWrite(SEGMENT_PINS[s], (pattern >> s) & 1);
  digitalWrite(DIGIT_PINS[which], LOW);
  delay(5);
}

void setup() {
  for (uint8_t i = 0; i < 8; i++) pinMode(SEGMENT_PINS[i], OUTPUT);
  for (uint8_t i = 0; i < 2; i++) {
    pinMode(DIGIT_PINS[i], OUTPUT);
    digitalWrite(DIGIT_PINS[i], HIGH);
  }
}

void loop() {
  if (millis() - lastCount >= 250) {
    lastCount = millis();
    count = (count + 1) % 100;
  }
  showDigit(0, FONT[count / 10]);
  showDigit(1, FONT[count % 10]);
}