int seg[] = {27,26,25,33,32,2,4}; //abcdefg
int tab[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7c,0x07,0x7f,0x67,0x00};

//int s1 = 23, s2 = 5, s3 = 18, s4 = 19;
int s[] = {23,5,18,19}, k, t;

void setup(void){
  for(int i = 0; i <= 3; i++){
    pinMode(s[i], OUTPUT);
  }
  for(int i = 0; i < 7; i++){
    pinMode(seg[i], OUTPUT);
    digitalWrite(seg[i],1);
  }
}

void display(int a){
  for(int i = 0; i < 7; i++){
    if(a%2 == 0){
      digitalWrite(seg[i], HIGH);
    }
    else{
      digitalWrite(seg[i], LOW);
    }
    a /= 2;
  }
}

void out(){
  digitalWrite(s[3],1);
  digitalWrite(s[2],0);
  digitalWrite(s[1],0);
  digitalWrite(s[0],0);
  display(tab[k%10]);
  delay(2);
  display(tab[10]);

  digitalWrite(s[3],0);
  digitalWrite(s[2],1);
  digitalWrite(s[1],0);
  digitalWrite(s[0],0);
  display(tab[k/10]);
  delay(2);
  display(tab[10]);
}

void loop(){
  k++;
  if(k>99){
    k = 0;
  }
  for(t = 0; t < 100; t++){
    out();
  }
}