int izq = 6
int dec = 2

void setup() {
Serial.begin(9600);
for (int led = 2; led<7;led = led+1){
  pinMode(led, OUTPUT);
}

}

void loop() {
for (int izq = 6; x <4; x = x+1){
  digitalWrite(x, HIGH);
  delay(30);
  digitalWrite(x, LOW);
  delay(30);

}

}