int i; // counter variable 
int j; // pgm outputs codes 00000  to 11111 in portd 2-7bits

void setup()
{
 DDRD = DDRD | B11111100;    // set direction bits for pins 2 to 7, leave 0 and 1 untouched               //(xx | 00 == xx)  same as pinMode(pin, OUTPUT) for pins 2 to 7
 Serial.begin(9600); 
} 

void loop()
{ 
for (i=0; i<64; i++)
  {                             // 6 bits manipulated 0 to 63
  PORTD = PORTD & B00000011;    // clear out bits 2 - 7, leave pins 0 and 1 untouched (xx & 11 == xx)
  j = (i << 2); // shift variable up to pins 2 - 7 - to avoid pins 0 and 1
  PORTD = PORTD | j; // combine the port information with the new information for LED pins 
  Serial.print("PORTD in BINary="); // debug to show masking
  Serial.println(PORTD, BIN); // debug to show masking 
  delay(2000); 
  }
}