void setup(){
  pinMode(2,OUTPUT);
  pinMode(3,OUTPUT);
  pinMode(4,OUTPUT);
  pinMode(5,OUTPUT);
}
void loop(){
  for(int i=16;i>0;i--){
    digitalWrite(2,(1<<0)&i);
    digitalWrite(3,(1<<1)&i);
    digitalWrite(4,(1<<2)&i);
    digitalWrite(5,(1<<3)&i);
    delay(3000);
  } 
     analogWrite(2,250);
     delay(2000);
     analogWrite(3,400);
     delay(2000);
     analogWrite(4,150);
     delay(2000);
     analogWrite(5,300);
     delay(2000);
  
}