void setup()
{
  // set pins 2 through 9 as output
  for (int i = 2; i <= 9; i++)
  {
    pinMode(i, OUTPUT); // initialize pins as outputs
  }
  Serial.begin(9600);
}

long i = 0;

void loop()
{
  // iterate over the pins
  // turn the LED on from lowest to the highest
  for (int a = 2; a <= 9; a++)
  {
    byte bitValue = bitRead(i, a - 2); // read the bit at position a - 2 from i
    Serial.print(bitValue);
    digitalWrite(a, bitValue); // turn the LED on or off based on the bit value
  }
  
  Serial.println(); // print a new line for clarity
  
  i++; // increment i
  
  if (i == 256) // reset i when it reaches 256
  {
    i = 0;
  }

  delay(100); // wait for 100 ms
}
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