#include <Arduino.h>
volatile int sequence = 0;

int button[] = {12, 26, 32};
int led[] = {13, 16, 33, 17 , 18, 19, 22, 23};

void sequence1_isr(){
  sequence = 1;
}
void sequence2_isr(){
  sequence = 2;
}
void sequence3_isr(){
  sequence = 3;
}
void sequence1();
void sequence2();
void sequence3();

void setup() {
  for (int i = 0; i < sizeof(button)  / sizeof (button[0]); i++) {
    pinMode(button[i] , INPUT_PULLUP);
    if (i = 0) {
      attachInterrupt(digitalPinToInterrupt(button[i]), sequence1_isr, FALLING);
    } 
    else if (i = 1) {
      attachInterrupt(digitalPinToInterrupt(button[i]), sequence2_isr, FALLING);
    } 
    else if (i = 2) {
      attachInterrupt(digitalPinToInterrupt(button[i]), sequence3_isr, FALLING);
    }
  }
  for (int i = 0; i < sizeof(led) / sizeof(led[0]); i++) {
    pinMode(led[i], OUTPUT);
  }
}
void loop(){
  if (sequence = 1) {
    sequence1();
  }
  else if (sequence = 2) {
    sequence2();
  }
  else if (sequence = 3) {
    sequence3();
  }
}
void sequence1(){
  for (int i = 0; i< sizeof(led) / sizeof(led[0]); i++){
    digitalWrite(led[i], HIGH);
    delay(500);
    digitalWrite(led[i], LOW);
  }
}
void sequence2() {
  int ledPairs[4][2] = {{13, 33}, {18, 22}, {34, 35}, {19, 23}};

  for ( int i = 0; i < 4; i++){
    digitalWrite(led[ledPairs[i][0]], HIGH);
    digitalWrite(led[ledPairs[i][1]], HIGH);
    delay(500);
    digitalWrite(led[ledPairs[i][0]], LOW);
    digitalWrite(led[ledPairs[i][1]], LOW);
  }
  for ( int i = 3; i > 0; i--){
     digitalWrite(led[ledPairs[i][0]], HIGH);
    digitalWrite(led[ledPairs[i][1]], HIGH);
    delay(500);
    digitalWrite(led[ledPairs[i][0]], LOW);
    digitalWrite(led[ledPairs[i][1]], LOW);
  }
}
void sequence3() {
  for ( int i = 0; i < 8; i += 2 ) {
    digitalWrite(led [i], HIGH);
    delay(500);
    digitalWrite(led [i], LOW);
  }
  for ( int i = 1; i < 8; i += 2){
    digitalWrite(led [i], HIGH);
    delay(500);
    digitalWrite(led [i], LOW);
  }
}