BlinkLoop

void setup() {
  for(int i=4;i<=13;i++) {
    pinMode(i,OUTPUT);
  }
  Serial.begin(9600);
}

void wave() {
  analogWrite(13,1);
  delay(500);
}

void pulse() {
  int led[] = {13,12,11,10,9,8,7,6,5,4};
  int pulseLength = 5;
  int delayLength = 100;

  int i = 0;
  while(true){
    digitalWrite(led[i%10],1);
    digitalWrite(led[(i-pulseLength)%10],0);
    delay(delayLength);
    i++;
  }
}

void loop() {

  pulse();
}