uint8_t light1=9;
uint8_t light2=10;
uint8_t button1=4;

void setup() 
{
  pinMode(light1, OUTPUT);
  pinMode(light2, OUTPUT);
  pinMode(button1, INPUT_PULLUP);

  analogWrite(light1, 0);
  analogWrite(light2, 0);
}

void loop() 
{
  int buttonState1;
  do {
    buttonState1 = digitalRead(button1);
  } while (buttonState1 == HIGH);

  for (int i=0; i<4; i++)
  {
    analogWrite(light1, 255);
    delay(100);
    analogWrite(light1, 0);
    delay(100);
  }
  for (int i=0; i<4; i++)
  {
    analogWrite(light2, 255);
    delay(100);
    analogWrite(light2, 0);
    delay(100);
  }
}