Stranger Things Ring lamp

#include <Adafruit_NeoPixel.h>

#define PIN_LED 4
#define NB_LED 68

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NB_LED, PIN_LED, NEO_GRB + NEO_KHZ800);

unsigned long debutCycle = 0;
unsigned long prochainEvent = 0;
bool flash = false;
unsigned long finFlash = 0;

void setup() {
  strip.begin();
  strip.show();
  randomSeed(analogRead(0));
  debutCycle = millis();
}

void loop() {
  unsigned long t = millis();

  // Durée exacte du cycle = 7000 ms (3s orage + 4s calme)
  unsigned long elapsed = t - debutCycle;

  // ----- RESTART CYCLE -----
  if (elapsed >= 7000) {
    debutCycle = t;
    elapsed = 0;
  }

  // ============================
  //       MODE ORAGE (0-3000 ms)
  // ============================
  if (elapsed < 3000) {

    // FIN D'UN FLASH
    if (flash && t >= finFlash) {
      flash = false;
      setRougeNormal();
      setBlancFixe();
      strip.show();
      prochainEvent = t + random(80, 200);
    }

    // DÉBUT D’UN FLASH
    if (!flash && t >= prochainEvent) {
      flash = true;
      finFlash = t + random(40, 120);

      setRougeFlash();
      setBlancFixe();
      strip.show();

      // Rafales aléatoires
      if (random(0, 10) < 4)
        prochainEvent = t + random(40, 120);
      else
        prochainEvent = finFlash + random(200, 500);
    }

    return;
  }

  // ============================
  //       MODE CALME (3000-7000 ms)
  // ============================
  flash = false;
  setRougeNormal();
  setBlancFixe();
  strip.show();
}



// =================================
//        FONCTIONS LED
// =================================

// Rouge flash fort (orage)
void setRougeFlash() {
  for (int i = 0; i < 12; i++)
    strip.setPixelColor(i, strip.Color(255, 0, 0));
  for (int i = 44; i < 68; i++)
    strip.setPixelColor(i, strip.Color(255, 0, 0));
}

// Rouge normal (calme)
void setRougeNormal() {
  for (int i = 0; i < 12; i++)
    strip.setPixelColor(i, strip.Color(40, 0, 0));
  for (int i = 44; i < 68; i++)
    strip.setPixelColor(i, strip.Color(40, 0, 0));
}

// LEDs blanches fixes
void setBlancFixe() {
  for (int i = 12; i < 44; i++)
    strip.setPixelColor(i, strip.Color(60, 60, 60));
}