#define led1 2
#define led2 0
#define led3 4
#define led4 16

void setup() {
  // put your setup code here, to run once:
  pinMode(led1,OUTPUT);
  pinMode(led2,OUTPUT);
  pinMode(led3,OUTPUT);
  pinMode(led4,OUTPUT);
  
}

void loop(){
  for(int i=0; i<=4;i++)
  {
    if(i==0)
    {
      digitalWrite(led1,LOW);
      digitalWrite(led2,LOW);
      digitalWrite(led3,LOW);
      digitalWrite(led4,LOW);
    }delay(100);

    if (i==1)
    {
      digitalWrite(led1,HIGH);
      digitalWrite(led2,LOW);
      digitalWrite(led3,LOW);
      digitalWrite(led4,LOW);
    }delay(100);

    if (i==2)
    {
      digitalWrite(led1,LOW);
      digitalWrite(led2,HIGH);
      digitalWrite(led3,LOW);
      digitalWrite(led4,LOW);
    }delay(100);

    if (i==3)
    {
      digitalWrite(led1,LOW);
      digitalWrite(led2,LOW);
      digitalWrite(led3,HIGH);
      digitalWrite(led4,LOW);
    }delay(100);

    if (i==4)
    {
      digitalWrite(led1,LOW);
      digitalWrite(led2,LOW);
      digitalWrite(led3,LOW);
      digitalWrite(led4,HIGH);
    }delay(100);
  }
}