Arduino Blink without delay

int oldmillis, currentmillis, oldmillis2, currentmillis2, oldmillis3, currentmillis3, interval = 1000, interval2 = 2000, interval3 = 3000;
bool time_past = LOW, pin = LOW, time_past2 = LOW, pin2 = LOW, time_past3 = LOW, pin3 = LOW;

// use #define to save memory instead of variables (byte LED = 1) for pins that don't change anyway
#define LED 1
#define LED2 2
#define LED3 3

void setup() {
  Serial.begin(9600);
  pinMode(LED, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
}

void loop() {

  // This part is executed every 1 seconds
  // *********** BEGIN *******************
  if (time_past == LOW) // set oldmillis with the current value of millis () only if time_past is LOW
  {
    oldmillis = millis();
    time_past = HIGH;
  }
  currentmillis = millis(); // get current millis () and save it in the variable currentmillis
  if ((currentmillis - oldmillis) > interval) // only do the following if currrentmillis-oldmillis is greater than interval (1 second has passed)
  {
    time_past = LOW; //Set status for time_past to LOW so that it can be reset
    pin = !pin; // negate the value of pin, make LOW to HIGH, make High to LOW
    digitalWrite(LED, pin); //write the new value of pin to the digital output
    if (pin) Serial.println("LED 1= ON");
    if (!pin) Serial.println("LED 1= OFF");
  }
  // ************ END *******************


  // This part is executed every 2 seconds
  // *********** BEGIN *******************
  if (time_past2 == LOW) // set oldmillis with the current value of millis () only if time_past is LOW
  {
    oldmillis2 = millis();
    time_past2 = HIGH;
  }
  currentmillis2 = millis(); // get current millis () and save it in the variable currentmillis
  if ((currentmillis2 - oldmillis2) > interval2) // only do the following if currrentmillis-oldmillis is greater than interval2 (2 second has passed)
  {
    time_past2 = LOW; //Set status for time_past to LOW so that it can be reset
    pin2 = !pin2; // negate the value of pin, make LOW to HIGH, make High to LOW
    digitalWrite(LED2, pin2); //write the new value of pin to the digital output
    if (pin2) Serial.println("LED 2= ON");
    if (!pin2) Serial.println("LED 2= OFF");
  }
  // ************ END *******************

  // This part is executed every 3 seconds
  // *********** BEGIN *******************
  if (time_past3 == LOW) // set oldmillis with the current value of millis () only if time_past is LOW
  {
    oldmillis3 = millis();
    time_past3 = HIGH;
  }
  currentmillis3 = millis(); // get current millis () and save it in the variable currentmillis
  if ((currentmillis3 - oldmillis3) > interval3) // only do the following if currrentmillis-oldmillis is greater than interval3 (3 second has passed)
  {
    time_past3 = LOW; //Set status for time_past to LOW so that it can be reset
    pin3 = !pin3; // negate the value of pin, make LOW to HIGH, make High to LOW
    digitalWrite(LED3, pin3); //write the new value of pin to the digital output
    if (pin3) Serial.println("LED 3= ON");
    if (!pin3) Serial.println("LED 3= OFF");
  }
  // ************ END *******************

}