const int LED_1 = 2;
const int LED_2 = 3;
const int LED_3 = 4;
const int LED_4 = 5;
const int LED_5 = 6;
const int LED_6 = 7;
const int LED_7 = 8;
const int LED_8 = 9;
const int LED_9 = 10;

void setup() {
  // put your setup code here, to run once:
pinMode (2, OUTPUT);
pinMode (3, OUTPUT);
pinMode (4, OUTPUT);
pinMode (5, OUTPUT);
pinMode (6, OUTPUT);
pinMode (7, OUTPUT);
pinMode (8, OUTPUT);
pinMode (9, OUTPUT);
pinMode (10, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite (4, HIGH);
digitalWrite (7, HIGH);
digitalWrite (8, HIGH);
delay (3000);
digitalWrite (4, LOW);
digitalWrite (7, LOW);
digitalWrite (8, LOW);
delay (100);
digitalWrite (3, HIGH);
digitalWrite (6, HIGH);
digitalWrite (8, HIGH);
delay (3000);
digitalWrite (3, LOW);
digitalWrite (6, LOW);
digitalWrite (8, LOW);
delay (100);
digitalWrite (2, HIGH);
digitalWrite (5, HIGH);
digitalWrite (8, HIGH);
delay (3000);
digitalWrite (2, LOW);
digitalWrite (5, LOW);
digitalWrite (8, LOW);
delay (100);
digitalWrite (2, HIGH);
digitalWrite (6, HIGH);
digitalWrite (9, HIGH);
delay (3000);
digitalWrite (2, LOW);
digitalWrite (6, LOW);
digitalWrite (9, LOW);
delay (100);
digitalWrite (3, HIGH);
digitalWrite (7, HIGH);
digitalWrite (10, HIGH);
delay (3000);
digitalWrite (3, LOW);
digitalWrite (7, LOW);
digitalWrite (10, LOW);
delay (100);
digitalWrite (3, HIGH);
digitalWrite (7, HIGH);
digitalWrite (9, HIGH);
delay (3000);
digitalWrite (3, LOW);
digitalWrite (7, LOW);
digitalWrite (9, LOW);
delay (100);
}