int i;
void setup() 
{
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, INPUT);
}
void loop()
{
  int state;
  state=digitalRead(5);
  if(state==1)
  {
    if(i==1)
    {
      digitalWrite(2, HIGH);
      delay(1000);
    }
    else if(i==2)
    {
      digitalWrite(3, HIGH);
      delay(1000);
    }
    else if(i==3)
    {
      digitalWrite(4, HIGH);
      delay(1000);
    }
    else if(i==4)
    {
      digitalWrite(2, LOW);
      digitalWrite(3, LOW);
      digitalWrite(4, LOW);
      i=0;
    }
    i++;
  }
}