class FlashingLed {
  private:
    byte ledPin;
    unsigned long onTime, offTime, lastMillis;

  public:
    FlashingLed(const byte pin, const unsigned long on, const unsigned long off) : ledPin(pin), onTime(on), offTime(off) {}

    void begin() {
      pinMode(ledPin, OUTPUT);
      digitalWrite(ledPin, HIGH);                   // Turn LED on
      lastMillis = millis();                        // remember when we did so
    }

    void flashWhenNeeded() {
      if (digitalRead(ledPin) == HIGH) {            // if the led is ON a it's the right time, turn it off (HIGH is on)
        if (millis() - lastMillis >= onTime) {      // check on time and turn LED off if time has expired
          lastMillis += onTime;                     // Add the value of onTime to lastMillis ready to start the next timing interval
          digitalWrite(ledPin, LOW);                // Turn LED off
        }
      } else {                                      // LED is off,  if it's the right time, turn it on
        if (millis() - lastMillis >= offTime) {     // check off time and turn LED on if time has expired
          lastMillis += offTime;                    // Add the value of offTime to lastMillis ready to start the next timing interval
          digitalWrite(ledPin, HIGH);               // Turn LED on
        }
      }
    }
};

FlashingLed leds[] = {
  {2, 500, 500},   // pin 2, 500ms ON and 500 ms OFF
  {3, 1750, 350}   // pin 3, 1750ms ON and 350ms OFF
}; 

void setup() {
  Serial.begin(115200);
  Serial.println(F(__FILE__));
  for (auto &l : leds) l.begin();
  Serial.println("Setup complete");
}

void loop() {
  for (auto &l : leds) l.flashWhenNeeded();
}