const int ledpin9 = 9;
const int ledpin8 = 8;
const int ledpin7 = 7;
const int ledpin6 = 6;
void setup() {
  pinMode(ledpin9, OUTPUT);
  pinMode(ledpin8, OUTPUT);
  pinMode(ledpin7, OUTPUT);
  pinMode(ledpin6, OUTPUT);
}

void loop() {
  digitalWrite(ledpin6, HIGH);
  digitalWrite(ledpin7, LOW);
  digitalWrite(ledpin8, LOW);
  digitalWrite(ledpin9, LOW);
  delay(500);
  digitalWrite(ledpin6, LOW);
  digitalWrite(ledpin7, HIGH);
  digitalWrite(ledpin8, LOW);
  digitalWrite(ledpin9, LOW);
  delay(500);
  digitalWrite(ledpin6, LOW);
  digitalWrite(ledpin7, LOW);
  digitalWrite(ledpin8, HIGH);
  digitalWrite(ledpin9, LOW);
  delay(500);
  digitalWrite(ledpin6, LOW);
  digitalWrite(ledpin7, LOW);
  digitalWrite(ledpin8, LOW);
  digitalWrite(ledpin9, HIGH);
  delay(500);
}