int leds[] = {10, 11, 12, 13};
int btns[] = {2, 3, 4, 5};
int bits[4] = {0, 0, 0, 0};
bool active = false;

void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(leds[i], OUTPUT);
    pinMode(btns[i], INPUT);
  }
  pinMode(6, INPUT);
}

void loop() {
  for (int i = 0; i < 4; i++) {
    if (digitalRead(btns[i]) == HIGH) {
      bits[i] = !bits[i];
      delay(300);
    }
  }

  if (digitalRead(6) == HIGH) {
    if (!active) {
      for (int i = 0; i < 4; i++) {
        digitalWrite(leds[i], bits[i]);
      }
      active = true;
    } 
    else {
      for (int i = 0; i < 4; i++) {
        digitalWrite(leds[i], LOW);
        bits[i] = 0;
      }
      active = false;
    }
    delay(300);
  }
}