// pin[xx] on led matrix connected to nn on Arduino (-1 is dummy to make array start at pos 1)
int pins[17]= {-1,13,18,4,3,17,2,16,15,5,0,14,7,1,11,6,12};

// row[xx] of leds = pin yy on led matrix
int cols[8] = {pins[13], pins[3], pins[4], pins[10], pins[06], pins[11], pins[15], pins[16]};

// col[xx] of leds = pin yy on led matrix
int rows[8] = {pins[9], pins[14], pins[8], pins[12], pins[1], pins[7], pins[2], pins[5]};


void setup() {
  // sets the pins as output
  for (int i = 1; i <= 16; i++) {
    pinMode(pins[i], OUTPUT);
  }
  
    // set up cols and rows
  for (int i = 1; i <= 8; i++) {
    digitalWrite(cols[i - 1], LOW);
  }

  for (int i = 1; i <= 8; i++) {
    digitalWrite(rows[i - 1], LOW);
  }
}

void loop() {
    display();
}

// Interrupt routine
void display() {
  
  digitalWrite(cols[0], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
  digitalWrite(cols[1], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
  digitalWrite(cols[2], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
   digitalWrite(cols[3], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);


   digitalWrite(cols[4], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
   digitalWrite(cols[5], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
    digitalWrite(cols[6], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
    digitalWrite(cols[7], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);
  
  digitalWrite(cols[8], HIGH);
  digitalWrite(rows[0], LOW);
  digitalWrite(rows[1], LOW);
  digitalWrite(rows[2], LOW);
  digitalWrite(rows[3], LOW);
  digitalWrite(rows[4], LOW);
  digitalWrite(rows[5], LOW);
  digitalWrite(rows[6], LOW);
  digitalWrite(rows[7], LOW);

}