const int ledpins[] = {13,12,11,10,9,8,7,6} ;
const int pb=2;
int mode =1;

void setup(){
Serial. begin(9600);
pinMode(pb, INPUT);

for (int i=0; i<8;i++){
pinMode(ledpins[i], OUTPUT);
}
}

void loop(){
  if(digitalRead(pb) == HIGH){
  mode++;

  if (mode >4){
    mode= 1;
  }
  Serial.print("Mode: ");
  Serial.println(mode);
  delay(400);
  }


switch (mode){

  case 1:
  for (int i =7; i>=0; i--){
    digitalWrite(ledpins[i], HIGH);
    delay(100);
    digitalWrite(ledpins[i], LOW);
  }
  break;

  case 2:
  for (int i=0; i<8; i++){
    digitalWrite(ledpins[i], HIGH);
    delay(100);
    digitalWrite(ledpins[i], LOW);
  }
  break;
  case 3 :
  for (int i =0; i<8; i++){
    digitalWrite(ledpins[i], HIGH);
  }
  delay(200);
  for (int i=0; i<8; i++){
    digitalWrite(ledpins[i], LOW);
  }
  delay(200);
  break;
  case 4:
  for (int i=0; i<8; i++){
    digitalWrite(ledpins[i], LOW);
  }
  break;
}
}