void setup() {
  RCC->AHBENR |= (1 << 1); //1 -> GPIOB
  GPIOB->MODER = 0x00005555;
  GPIOB->PUPDR = 0xA0000000;

  randomSeed(analogRead(0));
}

int value(int number) {
  int val;
  switch(number) {
    case 0: val = 0x3F;
    break;
    case 1: val = 0x06;
    break;
    case 2: val = 0x5B;
    break;
    case 3: val = 0x4F;
    break;
    case 4: val = 0x66;
    break;
    case 5: val = 0x6D;
    break;
    case 6: val = 0xFD;
    break;
    case 7: val = 0x07;
    break;
    case 8: val = 0x7F;
    break;
    case 9: val = 0xEF;
    break;
    default: val = 0x00;
    break;
  }
  return val;
}

void running() {
  for (int a = 50; a <= 250; a = a + 50) {
    for (int i = 0; i <= 9; i++) {
      GPIOB->ODR = value(i);
      delay(a);
    }
  }
}

void ending(int step) {
  int wait = 300;
  int row = 0;

  do {
    GPIOB->ODR = value(row);
    delay(wait);
    row++;
    wait *= 1.2;
  } while (row <= step);
}

int x = 0;
int zufall = 0;

void loop() {
  if (GPIOB->IDR >= 1028) {
    GPIOB->ODR = 0x00;
    delay(100);
    zufall = random(0, 10);
    running();
    ending(zufall);
    GPIOB->ODR = value(zufall);
    delay(500);
  }
  delay(10);
}