const int row[8] = {
  2,3,4,5,6,7,8,9  };

const int col[8] = {
  10,11,12,13,14,15,16,17  };
  
void setup() {
  // initialize the I/O pins as outputs:

  // iterate over the pins:
  for (int thisPin = 0; thisPin < 8; thisPin++) {
    // initialize the output pins:
    pinMode(col[thisPin], OUTPUT);
    pinMode(row[thisPin], OUTPUT);
    // take the col pins (i.e. the cathodes) high to ensure that
    // the LEDS are off: 
    digitalWrite(col[thisPin], HIGH);
  }
}

void loop() {
  // iterate over the rows (anodes):
  for (int thisRow = 0; thisRow < 8; thisRow++) {
    // take the row pin (anode) high:
    digitalWrite(row[thisRow], HIGH);
    // iterate over the cols (cathodes):
    for (int thisCol = 0; thisCol < 8; thisCol++) {

      // when the row is HIGH and the col is LOW,
      // the LED where they meet turns on:
      digitalWrite(col[thisCol], LOW);
      // wait a few milliseconds to see it:
      delay(30);
      // turn the pixel off:
      digitalWrite(col[thisCol], HIGH);
    }
    // take the row pin low to turn off the whole row:
    digitalWrite(row[thisRow], LOW);
  }
}