unsigned long currentTime=0;
unsigned long previousTime=0;
unsigned long interval,interval1=200, interval2=200;
bool ledState=LOW;
int compteur=0;
int vitesse=1200;
int x;
void setup() {

  pinMode(6,OUTPUT);
	pinMode(3,OUTPUT);
	pinMode(4,OUTPUT);
	pinMode(5,OUTPUT);
}

void loop() {

	// digitalWrite(6,HIGH);
  analogWrite(6, 200);

if (vitesse >= 50) {

  digitalWrite(3, HIGH);   
  delay(vitesse);             
  digitalWrite(3, LOW);    
  delay(100);                      

  digitalWrite(4, HIGH);   
  delay(vitesse);             
  digitalWrite(4, LOW);   
  delay(100);             

  digitalWrite(5, HIGH);  
  delay(vitesse);             
  digitalWrite(5, LOW);   
  delay(100);

  vitesse = vitesse-50;
  }
else {
    vitesse = 1200;
    x=0;
// Allumer progressivement la LED (0 --> 255)
  while (x <= 225) {
    analogWrite(6, x);
    delay(50);
    x = x + 1;
  }

  // Eteindre progressivement la LED (255 --> 0)
  x = 225;
  while (x >= 0) {   

    analogWrite(6, x);
    delay(50);
    x = x - 1;
  }

}

}