const int pinLED1 = 1;
const int pinLED2 = 2;
const int pinLED3 = 3;
const int pinLED4 = 4;
void setup() {
  // put your setup code here, to run once:
pinMode(pinLED1, OUTPUT); 
pinMode(pinLED2, OUTPUT);
pinMode(pinLED3, OUTPUT);
pinMode(pinLED4, OUTPUT);
}
void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(pinLED1,LOW);
digitalWrite(pinLED2,LOW);
digitalWrite(pinLED3,LOW);
digitalWrite(pinLED4,LOW);
delay(1000);
digitalWrite(pinLED1, HIGH);
delay(1000);
digitalWrite(pinLED2, HIGH);
delay(1000);
digitalWrite(pinLED3, HIGH);
delay(1000);
digitalWrite(pinLED4, HIGH);
delay(1000);
  }