const int LED1=2, LED2=4;
void setup() {
pinMode(LED1, OUTPUT);
//digitalWrite(LED, HIGH);
pinMode(LED2, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
for (int i=100; i<=1000; i=i+100)
{
digitalWrite(LED1, HIGH);
delay(i);
digitalWrite(LED1, LOW);
delay(i);
digitalWrite(LED2, HIGH);
delay(i);
digitalWrite(LED2, LOW);
delay(i);
}
}