int switchState = 0;
int lastSwitchState = 0;
int count = 0;

void setup() {
  pinMode(2,INPUT);

  Serial.begin(9600); // debug
}

void loop() {
  // counter
  switchState = digitalRead(2);
  if (switchState == HIGH && lastSwitchState == 0){ 
    count++;
    if (count > 13){
      count = 0;
    }
    lastSwitchState = 1;
  }
  else if (switchState == LOW){
    lastSwitchState = 0;
  }

  // charlieplex
  if (count == 0){
    pinMode(3, OUTPUT);
    digitalWrite(3,LOW);
    pinMode(4, OUTPUT);
    digitalWrite(4,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5,LOW);
    pinMode(6, OUTPUT);
    digitalWrite(6,LOW);
  }
  else if (count == 1){
    pinMode(6, INPUT);
    digitalWrite(6,LOW);
    pinMode(5, INPUT);
    digitalWrite(5, LOW);  
    pinMode(4, OUTPUT);
    digitalWrite(4, LOW);  
    pinMode(3, OUTPUT);
    digitalWrite(3, HIGH);
  }
  else if (count == 2){
    pinMode(6, INPUT);
    digitalWrite(6,LOW);
    pinMode(5, INPUT);
    digitalWrite(5, LOW);  
    pinMode(4, OUTPUT);
    digitalWrite(4, HIGH);  
    pinMode(3, OUTPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 3){
    pinMode(6, INPUT);
    digitalWrite(6,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5, LOW);  
    pinMode(4, OUTPUT);
    digitalWrite(4, HIGH);  
    pinMode(3, INPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 4){
    pinMode(6, INPUT);
    digitalWrite(6,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5, HIGH);  
    pinMode(4, OUTPUT);
    digitalWrite(4, LOW);  
    pinMode(3, INPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 5){
    pinMode(6, OUTPUT);
    digitalWrite(6,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5, HIGH);  
    pinMode(4, INPUT);
    digitalWrite(4, LOW);  
    pinMode(3, INPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 6){
    pinMode(6, OUTPUT);
    digitalWrite(6,HIGH);
    pinMode(5, OUTPUT);
    digitalWrite(5, LOW);  
    pinMode(4, INPUT);
    digitalWrite(4, LOW);  
    pinMode(3, INPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 7){
    pinMode(6, INPUT);
    digitalWrite(6,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5, HIGH);  
    pinMode(4, INPUT);
    digitalWrite(4, LOW);  
    pinMode(3, OUTPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 8){
    pinMode(6, INPUT);
    digitalWrite(6,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5, LOW);  
    pinMode(4, INPUT);
    digitalWrite(4, LOW);  
    pinMode(3, OUTPUT);
    digitalWrite(3, HIGH);
  }
  else if (count == 9){
    pinMode(6, OUTPUT);
    digitalWrite(6,LOW);
    pinMode(5, INPUT);
    digitalWrite(5, LOW);  
    pinMode(4, INPUT);
    digitalWrite(4, LOW);  
    pinMode(3, OUTPUT);
    digitalWrite(3, HIGH);
  }
  else if (count == 10){
    pinMode(6, OUTPUT);
    digitalWrite(6,HIGH);
    pinMode(5, INPUT);
    digitalWrite(5, LOW);  
    pinMode(4, INPUT);
    digitalWrite(4, LOW);  
    pinMode(3, OUTPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 11){
    pinMode(6, OUTPUT);
    digitalWrite(6,HIGH);
    pinMode(5, INPUT);
    digitalWrite(5, LOW);  
    pinMode(4, OUTPUT);
    digitalWrite(4, LOW);  
    pinMode(3, INPUT);
    digitalWrite(3, LOW);
  }
  else if (count == 12){
    pinMode(6, OUTPUT);
    digitalWrite(6,LOW);
    pinMode(5, INPUT);
    digitalWrite(5, LOW);  
    pinMode(4, OUTPUT);
    digitalWrite(4, HIGH);  
    pinMode(3, INPUT);
    digitalWrite(3, LOW);
  }
  // TEST COUNTER number 13
  // test 1) LED 1 and 2 on at the same time: NOT POSSIBLE
  // test 2) HHHL (line 3 L) LED 2-7-10 are on: POSSIBLE
  // test 3) HHLL (line 3 & 4 H) LED 3-8-9-12 are one: POSSIBLE
  else if (count == 13){
    pinMode(6, OUTPUT);
    digitalWrite(6,LOW);
    pinMode(5, OUTPUT);
    digitalWrite(5, LOW);  
    pinMode(4, OUTPUT);
    digitalWrite(4, HIGH);  
    pinMode(3, OUTPUT);
    digitalWrite(3, HIGH);
  }

  // debug lines
  Serial.print("count number: ");
  Serial.println(count);
}