int potPin = 2;    // select the input pin for the potentiometer
int ledPin0 = 13;
int ledPin1 = 12;
int ledPin2 = 7;   // select the pin for the LED
int val = 0;       // variable to store the value coming from the sensor

void setup() {
  pinMode(ledPin0, OUTPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);  // declare the ledPin as an OUTPUT
}

void loop() {
  val = analogRead(potPin);
      // read the value from the sensor
  digitalWrite(ledPin0, LOW);
  digitalWrite(ledPin1, LOW);
  digitalWrite(ledPin2, HIGH);  // turn the ledPin on
  delay(val);
                    // stop the program for some time
  digitalWrite(ledPin0, LOW);
  digitalWrite(ledPin1, HIGH);
  digitalWrite(ledPin2, LOW);   // turn the ledPin off
  delay(val);
  
  digitalWrite(ledPin0, HIGH);
  digitalWrite(ledPin1, LOW);
  digitalWrite(ledPin2, LOW);   // turn the ledPin off
  delay(val);                  // stop the program for some time
}