int pin[7] = {32, 33, 25, 26, 27, 14, 12};
int number[10] = {1, 79, 18, 6, 76, 36, 32, 15, 0, 12};
// int seg[4] = {15, 5, 18, 19};
int seg[4] = {19, 18, 5, 15};
int k = 0, digits = 2;
int bottom = 4;
bool on = 0;

void display(int number){
  for(int i = 6; i >= 0; i--){
    digitalWrite(pin[i], number % 2);
    number /= 2;
  }
}

void setup() {
  pinMode(bottom, INPUT_PULLUP);
  for(int i = 0; i < 4 ; i++){
    pinMode(seg[i], OUTPUT);
  }
  for(int i = 0; i < 7; i++){
    pinMode(pin[i], OUTPUT);
    digitalWrite(pin[i], HIGH);
  }
}

void out() {
  int num = k;
  for(int i = 0; i < 4 - digits; i++){
    for(int j = 0; j < 4 - digits; j++){
      digitalWrite(seg[j], i == j);
    }

    display(number[num % 10]);
    delay(2);

    for(int j = 0; j < 7; j++)
      digitalWrite(pin[j], HIGH);

    num /= 10;
  }
}

int add = 1;

void loop() {
  while(!on){
    if(!digitalRead(bottom)){
      on = !on;
    }
  }

  for(int i = 0; i < 50; i++){
    out();
  }

  if(!digitalRead(bottom)){
    add = -add;
  }
  k += add;

  if(k >= 20 && add == 1){
    k = 20;
  }

  if(k < 0){
    k = 36;
  }
}