#define BUTTON 3
int val = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode (BUTTON, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  val = digitalRead(BUTTON);

  if (val == LOW) {
    digitalWrite(6, HIGH);
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);
  delay(500);
  
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
  digitalWrite(8, LOW);
  delay(500);

  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, HIGH);
  delay(500);
  } 
  else { 
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, HIGH);
  delay(500);
  
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
  digitalWrite(8, LOW);
  delay(500);

  digitalWrite(6, HIGH);
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);
  delay(500);
  }
}