// C++ code
//
void setup()
{
  for(int i=2;i<=4;i++)
     pinMode(i, OUTPUT);
}
unsigned long led1=0;
unsigned long led2=0;
unsigned long led3=0;
int led1status=0;
int led2status=0;
int led3status=0;
void loop()
{
  if( millis()- led1 >= 250&&led1status==0)
  {
   led1=millis();
   digitalWrite(2,1);
   led1status=1;
  } else if( millis()- led1 >= 500&&led1status==1)
  {
   led1=millis();
   digitalWrite(2,0);
   led1status=0;     
  }
    
  
    if( millis()- led2 >= 250&&led2status==0)
  {
   led2=millis();
   digitalWrite(3,1);
   led2status=1;
  } else if( millis()- led2 >= 250&&led2status==1)
  {
   led2=millis();
   digitalWrite(3,0);
   led2status=0;     
  }
  
    
    if( millis()- led3 >= 1000&&led3status==0)
  {
   led3=millis();
   digitalWrite(4,1);
   led3status=1;
  } else if( millis()- led3 >= 1000&&led3status==1)
  {
   led3=millis();
   digitalWrite(4,0);
   led3status=0;     
  }
   
}