const int8_t L1 = 19;
const int8_t BT1 = 10;
unsigned long buttonPressedAt = 0;
unsigned long buttonReleasedAt = 0;

const int8_t L2 = 18;
const int8_t BT2 = 1;
const int8_t L3 = 4;
const int8_t BT3 = 0;
const int8_t L4 = 6;
const int8_t BT4 = 3;

void setup() {
  // put your setup code here, to run once:
    pinMode(L1, OUTPUT);
    pinMode(BT1, OUTPUT);

    pinMode(L2, OUTPUT);
    pinMode(BT2, OUTPUT);

    pinMode(L3, OUTPUT);
    pinMode(BT3, OUTPUT);

    pinMode(L4, OUTPUT);
    pinMode(BT4, OUTPUT);
}

void loop() {

    if (digitalRead(BT1) == LOW) {
      digitalWrite(L1, HIGH);
    } else {
        digitalWrite(L1, LOW);
    }

    if (digitalRead(BT2) == LOW) {
      digitalWrite(L2, HIGH);
    } else {
        digitalWrite(L2, LOW);
    }

    if (digitalRead(BT3) == LOW) {
      digitalWrite(L3, HIGH);
    } else {
        digitalWrite(L3, LOW);
    }

    if (digitalRead(BT4) == LOW) {
      digitalWrite(L4, HIGH);
    } else {
        digitalWrite(L4, LOW);
    }
}

void f(){
  digitalWrite(L1, HIGH);
}