void setup(){
Serial.begin(9600);
pinMode(2,INPUT_PULLUP);
pinMode(3,OUTPUT);
pinMode(4,OUTPUT);
pinMode(5,OUTPUT);
pinMode(6,OUTPUT);
}
void loop(){
  int s=digitalRead(2);
  if(s==1)
  {
    for(int i=0;i<16;i++)
    {
      digitalWrite(3,(1<<0))&i);
      digitalWrite(4,(1<<1))&i);
      digitalWrite(5,(1<<2))&i);
      digitalWrite(6,(1<<3))&i);
      delay(1000);
    }
  }
  else if (s==0)
  {
    for (int j=0;j<16;j--)
    {
      digitalWrite(3,(1<<0)&j);
      digitalWrite(4,(1<<1)&j);
      digitalWrite(5,(1<<2)&j);
      digitalWrite(6,(1<<3)&j);
    }
  }
}