int led = 13;

void setup() {
  
  Serial.begin(9600);
  pinMode(led, OUTPUT);

  // Count to 10, but replace the number 5 with the word "five"
  for ( int i = 1; i <= 10; i++ ) {
    if ( i == 5 ) {
      Serial.println("five");
    } else {
      Serial.println(i);
    }
  }
}
void loop() {

  int ms = 200;

  // Make the LED flash faster and faster until it appears as
  // a static light. Reset when the delay reaches 0 ms.
  while ( ms > 0 ) {
    digitalWrite(led, HIGH);
    delay(ms);
    digitalWrite(led, LOW);
    delay(ms);
    ms -= 5;
  }
}

Simulator: https://tinkercad.com/things/3Zoxt5XXQiA