/*
This program will turn on LEDs in pairs and turn them off in pairs in reverse order. There is a 2 second delay in between each turn-on and turn-off events.
*/

// Initialise LEDs
int led1 = 13;
int led2 = 8;
int led3 = 12;
int led4 = 9;
int led5 = 11;
int led6 = 10;

//Initialise buzzer
int buzzer = 3;

void setup(){
// Initialise the pins as output
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
pinMode(led4, OUTPUT);
pinMode(led5, OUTPUT);
pinMode(led6, OUTPUT);
pinMode(buzzer, OUTPUT);

executeLEDAndBuzzerSteps();
}

void executeLEDAndBuzzerSteps() {

digitalWrite(led1, HIGH);
digitalWrite(led2, HIGH);
tone(buzzer, 250, 20);
delay(2000);

digitalWrite(led3, HIGH);
digitalWrite(led4, HIGH);
tone(buzzer, 350, 20);
delay(2000);

digitalWrite(led5, HIGH);
digitalWrite(led6, HIGH);
tone(buzzer, 450, 20);
delay(2000);

digitalWrite(led5, LOW);
digitalWrite(led6, LOW);
tone(buzzer, 450, 20);
delay(2000);

digitalWrite(led3, LOW);
digitalWrite(led4, LOW);
tone(buzzer, 350, 20);
delay(2000);

digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
tone(buzzer, 250, 20);
}

void loop() {
//Mandatory function
//executeLEDAndBuzzerSteps();
}