DS3231 + TM1637 + arduino clock

#include <Wire.h>
#include <Sodaq_DS3231.h>
#include <TM1637Display.h>
#include <Arduino.h>

#define CLK 3
#define DIO 2

TM1637Display display(CLK, DIO);
//            yyyy, mm, dd, hh, mm, ss, dd
//DateTime dt(2017, 10, 30, 17, 20, 30, 0);
DateTime now;


const uint8_t SEG_8421[] = {
  SEG_A | SEG_B | SEG_C | SEG_D | SEG_E | SEG_F | SEG_G, // 8
  SEG_F | SEG_G | SEG_B | SEG_C, // 4
  SEG_A | SEG_B | SEG_G | SEG_E | SEG_D, // 2
  SEG_B | SEG_C // 1
};

void setup() {
  Wire.begin();
  rtc.begin();
//  rtc.setDateTime(dt);

  display.setBrightness(0x09);
  display.setSegments(SEG_8421);
  delay(1000);
}

uint32_t old_TimeStamp;

void loop() {
  DateTime now = rtc.now();
  for(int i = 0; i < 14; i++){
    display.showNumberDec(now.hour() * 100 + now.minute(), true, 4, 0);
    delay(500);
  }
  for(int j = 0; j < 2; j++){
    display.showNumberDec(now.second(), false, 4, 0);
    delay(500);
  }

}