fun cs peek-number-light bomb for arduino

int a = 1;
int b = 2;
int c = 3;
int d = 4;
int e = 5;
int f = 6;
int g = 7;
int dp = 8;

int d4 = 9;
int d3 = 10;
int d2 = 11;
int d1 = 12;

// set variable
long n = 1230;
int x = 100;
int del = 55;    // fine adjustment for clock

int ledPin = 14;// define digital interface 13
int peekPin = 15;// define digital interface 13

long timeToExplode = 40000;

long startTime;
int peekTime = 75;
int pauseTime = 1125;

void setup() {
  pinMode(d1, OUTPUT);
  pinMode(d2, OUTPUT);
  pinMode(d3, OUTPUT);
  pinMode(d4, OUTPUT);
  pinMode(a, OUTPUT);
  pinMode(b, OUTPUT);
  pinMode(c, OUTPUT);
  pinMode(d, OUTPUT);
  pinMode(e, OUTPUT);
  pinMode(f, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(dp, OUTPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(peekPin, OUTPUT);
  startTime = millis();
}
/////////////////////////////////////////////////////////////

void loop() {
//  Serial.begin(9600);
  
  Serial.println("Peeeeee...");
  digitalWrite(ledPin, HIGH);
  digitalWrite(peekPin, HIGH);
  
  
  if (timeLeft() < 0) {
    Serial.println("Boom");
    showBoom(1500);
    digitalWrite(ledPin, LOW);
    digitalWrite(peekPin, LOW);
    exit(0);
    return;
  }
  showTime(peekTime);
  Serial.println("...eeeeeek!");
  digitalWrite(ledPin, LOW);
  digitalWrite(peekPin, LOW);
  
  showTime(pauseTime);
  pauseTime = (int)(1125 * (((float)timeLeft()) / ((float)timeToExplode)));
  Serial.print("Time left: ");
  Serial.print((float)timeLeft() / 1000);
  Serial.println("s");
  Serial.print("Pause time: ");
  Serial.println((((float)timeLeft()) / ((float)timeToExplode)));
  
  
}

void showTime(int duration){
  long showingTime = millis();
  do {
    long t = timeLeft();
    Display(1, (t / 1000000) % 10);
    Display(2, (t / 100000) % 10);
    Display(3, (t / 10000) % 10);
    Display(4, (t / 1000) % 10);
  } while(millis() - showingTime < duration);
}

void showBoom(int duration){
  long showingTime = millis();
  do {
    long t = timeLeft();
    Display(1, 8);
    Display(2, 0);
    Display(3, 0);
    Display(4, 0);
  } while(millis() - showingTime < duration);
  ClearAll() ; // clear the screen
}

long timeLeft() {
  return timeToExplode - (millis() - startTime);
}
///////////////////////////////////////////////////////////////
void WeiXuan(unsigned char n) {
  switch (n) {
    case 1:
      digitalWrite(d1, LOW);
      digitalWrite(d2, HIGH);
      digitalWrite(d3, HIGH);
      digitalWrite(d4, HIGH);
      break;
    case 2:
      digitalWrite(d1, HIGH);
      digitalWrite(d2, LOW);
      digitalWrite(d3, HIGH);
      digitalWrite(d4, HIGH);
      break;
    case 3:
      digitalWrite(d1, HIGH);
      digitalWrite(d2, HIGH);
      digitalWrite(d3, LOW);
      digitalWrite(d4, HIGH);
      break;
    case 4:
      digitalWrite(d1, HIGH);
      digitalWrite(d2, HIGH);
      digitalWrite(d3, HIGH);
      digitalWrite(d4, LOW);
      break;
    default :
      digitalWrite(d1, HIGH);
      digitalWrite(d2, HIGH);
      digitalWrite(d3, HIGH);
      digitalWrite(d4, HIGH);
      break;
  }
}
void Num_0() {
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, LOW);
  digitalWrite(dp, LOW);
}
void Num_1() {
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp, LOW);
}
void Num_2() {
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, LOW);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Num_3() {
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Num_4() {
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Num_5()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Num_6()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Num_7()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp, LOW);
}
void Num_8()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Num_9()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp, LOW);
}
void Clear() {  
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp, LOW);
}
void ClearAll() {
  WeiXuan(1);
  Clear();
  WeiXuan(2);
  Clear();
  WeiXuan(3);
  Clear();
  WeiXuan(4);
}
void pickNumber(unsigned char n) {// select number
  switch (n) {
    case 0: Num_0();
      break;
    case 1: Num_1();
      break;
    case 2: Num_2();
      break;
    case 3: Num_3();
      break;
    case 4: Num_4();
      break;
    case 5: Num_5();
      break;
    case 6: Num_6();
      break;
    case 7: Num_7();
      break;
    case 8: Num_8();
      break;
    case 9: Num_9();
      break;
    default: Clear();
      break;
  }
}
void Display(unsigned char x, unsigned char Number) {//    take x as coordinate and display number
  delay(1);
  Clear() ; // clear the screen
  WeiXuan(x);
  pickNumber(Number);
}