int redLED = 23;    
int greenLED = 22;  
int blueLED = 21;
int skyblueLED = 19;
int whiteLED = 18;

void setup() {
  pinMode(redLED, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(blueLED, OUTPUT);
  pinMode(skyblueLED, OUTPUT);
  pinMode(whiteLED, OUTPUT);
}

void loop() {
  // Blink the red LED
  digitalWrite(redLED, LOW);
  digitalWrite(greenLED, HIGH);
  delay(500);
  digitalWrite(greenLED, LOW); 
  delay(1000);
  digitalWrite(blueLED, HIGH);
  delay(500);
  digitalWrite(blueLED, LOW);
  delay(1000);
  digitalWrite(skyblueLED, HIGH);
  delay(500);
  digitalWrite(skyblueLED, LOW);
  delay(1000);
  digitalWrite(whiteLED, HIGH);
  delay(500);
  digitalWrite(whiteLED, LOW);
  delay(1000);
}