1b

#define LED_GREEN 12
#define LED_RED 11
unsigned long old_green_millis = millis();
unsigned long old_red_millis = millis();
int max_interval = 1000;
int min_interval = 10;

void setup() {
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_RED, OUTPUT);
  Serial.begin(9600);

}

void loop() {
  int green_interval = max_interval;
  int red_interval = min_interval;

  while ((green_interval >= min_interval) and
         (red_interval <= max_interval)) {

    if (millis() - old_green_millis >= green_interval) {
      digitalWrite(LED_GREEN, !digitalRead(LED_GREEN));
      green_interval -= 20;
      old_green_millis = millis();
    }

    if (millis() - old_red_millis >= red_interval) {
      digitalWrite(LED_RED, !digitalRead(LED_RED));
      red_interval += 10;
      old_red_millis = millis();
    }
  }
  Serial.println("UTE");
}