#define LED1 2
#define LED2 3
#define LED3 4

bool state1 = false;
bool state2 = false;
bool state3 = false;

int millis1;
int millis2;
int millis3;

void timer1();
void timer2();
void timer3();

void toggle1();
void toggle2();
void toggle3();


void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
}

void loop() {
  timer1();
  timer2();
  timer3();
}

void timer1() {
  if (millis() - millis1 >= 200) {
    millis1 = millis();
    toggle1();
  }
}

void timer2() {
  if (millis() - millis2 >= 500) {
    millis2 = millis();
    toggle2();
  }
}

void timer3() {
  if (millis() - millis3 >= 900) {
    millis3 = millis();
    toggle3();
  }
}

void toggle1() {
  state1 = !state1;
  digitalWrite(LED1, state1);
}

void toggle2() {
  state2 = !state2;
  digitalWrite(LED2, state2);
}

void toggle3() {
  state3 = !state3;
  digitalWrite(LED3, state3);
}