I used Arduino with a green LED. I changed the code to lighting up for 2 seconds and then off for 4 seconds. Uploaded the code and made sure that it has changed.

Components

• 1 Arduino
• 1 LED
• 1 Resistor (220Ω)
• 1 Breadboard

Code

/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
This example code is in the public domain.
*/

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
  delay(2000); // wait for 2 second
  digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
  delay(4000); // wait for 4 second
}