int led= 12; 
void setup() 
{
 pinMode(led, OUTPUT); 
}

void loop() 
{
  digitalWrite(led, HIGH);
  delay (2);
  for(int i= 0; i<2; i++)
  {
    digitalWrite(led, LOW); // 0
    delayMicroseconds(500);
    digitalWrite(led, HIGH);
    delayMicroseconds(500);
  }
  for(int j= 0; j<2; j++)
  {
    digitalWrite(led, HIGH); // 1
    delayMicroseconds(500);
    digitalWrite(led, LOW);
    delayMicroseconds(500);
  }
  for(int j= 0; j<2; j++)
  {
    digitalWrite(led, HIGH); // 1
    delayMicroseconds(500);
    digitalWrite(led, LOW);
    delayMicroseconds(500);
  }
  for(int i= 0; i<2; i++)
  {
    digitalWrite(led, LOW); // 0
    delayMicroseconds(500);
    digitalWrite(led, HIGH);
    delayMicroseconds(500);
  }
  for(int i= 0; i<2; i++)
  {
    digitalWrite(led, LOW); // 0
    delayMicroseconds(500);
    digitalWrite(led, HIGH);
    delayMicroseconds(500);
  }

}