int a=12;
int b=11;
int c=10;

unsigned long pm = 0;
const long interval = 1000;  // Интервал в мс
int interval2=10000;
int interval3=5000;
int interval4=3000;

void setup() {
  Serial.begin(9600);
 pinMode(12, OUTPUT);
 pinMode(11, OUTPUT);
 pinMode(10, OUTPUT);

}

void loop() {

 unsigned long cm = millis();
  if (cm - pm >= interval) {
    pm = cm;
    Serial.println("Прошла 1 секунда");
  }

  if(pm<=interval2){
    digitalWrite(12, HIGH);
    if(cm>interval2){
      digitalWrite(12, LOW);
    }
  }
  if(pm<=interval2){
    digitalWrite(12, HIGH);
    if(cm>interval2){
      digitalWrite(12, LOW);
    }
  }
/*
  digitalWrite(12, HIGH);
  delay(10000);
  digitalWrite(12, LOW);
  delay(1000);
  digitalWrite(11, HIGH);
  delay(5000);
  digitalWrite(11, LOW);
  delay(1000);
  digitalWrite(10, HIGH);
  delay(3000);
  digitalWrite(10,LOW);
  delay(1000);

  for(int i=0;i<4;i++){
    digitalWrite(10, HIGH);
    delay(500);
    digitalWrite(10, LOW);
    delay(500);
  }
  */

}