int led1 = 2;
int led2 = 3;
int led3 = 4;
int led4 = 5;
int led5 = 6;
int led6 = 7;
int led7 = 8;
int randNr;
int randNrOld;
int taster = 10;
int iButtenState;
int iUeberschl;
int iSpeed;

void setup() {
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(led7, OUTPUT);
  pinMode(taster, INPUT);
  randomSeed(analogRead(0));
  Serial.begin(9600);
}
void loop() {

  iButtenState = digitalRead(taster);
  iUeberschl = random(5, 16);
  if (iButtenState == HIGH) {
    for (int i = 0; i < iUeberschl; i++) {
      do {
        randNr = random(1, 7);
      } while ((randNrOld == randNr) || (randNrOld + randNr == 7));
      randNrOld = randNr;

      iSpeed = (50 / iUeberschl) + (i * (500 / iUeberschl));
      Serial.print("Speed = ");
      Serial.println(iSpeed);
      delay(iSpeed);

      digitalWrite(led1, LOW);
      digitalWrite(led2, LOW);
      digitalWrite(led3, LOW);
      digitalWrite(led4, LOW);
      digitalWrite(led5, LOW);
      digitalWrite(led6, LOW);
      digitalWrite(led7, LOW);

      delay(iSpeed);
      
      if (randNr == 1) {
        digitalWrite(led1, HIGH);
      }  // 1
      if (randNr == 2) {
        digitalWrite(led2, HIGH);
        digitalWrite(led3, HIGH);
      }  //2
      if (randNr == 3) {
        digitalWrite(led1, HIGH);
        digitalWrite(led2, HIGH);
        digitalWrite(led3, HIGH);
      }  //3
      if (randNr == 4) {
        digitalWrite(led2, HIGH);
        digitalWrite(led3, HIGH);
        digitalWrite(led4, HIGH);
        digitalWrite(led5, HIGH);
      }  //4
      if (randNr == 5) {
        digitalWrite(led1, HIGH);
        digitalWrite(led2, HIGH);
        digitalWrite(led3, HIGH);
        digitalWrite(led4, HIGH);
        digitalWrite(led5, HIGH);
      }  //5
      if (randNr == 6) {
        digitalWrite(led2, HIGH);
        digitalWrite(led3, HIGH);
        digitalWrite(led4, HIGH);
        digitalWrite(led5, HIGH);
        digitalWrite(led6, HIGH);
        digitalWrite(led7, HIGH);
      }  //6
    }
  }
}