#define DelayTime 10
#define ROW 8
#define COL 3
#define G1 13

const int scan[COL] = {10,11,12};
const int row[ROW] = {2,3,4,5,6,7,8,9};

void setup() {
  for (int i = 0;i<COL;i++) pinMode(scan[i], OUTPUT);
  for (int i = 0;i<ROW;i++) pinMode(row[i], OUTPUT);
  pinMode(G1, OUTPUT);
  digitalWrite(G1,HIGH);
}
int i=0, dy=1, dx=1, t=0;
void loop() {
  int r, u;
  digitalWrite(scan[2],i & 4);digitalWrite(scan[1],i & 2);digitalWrite(scan[0],i & 1);
  i+=dy;
  if(i<0){
    i=1;dy=1;
  }
  else if(i>=ROW){
    i=ROW-2;dy=-1;
  }
  for(r=0;r<ROW;r++){
     for(u=0;u<ROW;u++){
        digitalWrite(row[u],(u==t));
        delay(DelayTime);
     }
     t+=dx;
     if(t<0){
        dx=1;t=0;
     }
     else if(t>=ROW){
        dx=-1;t=ROW-1;
     }
  }
}