word   KeyDown, KeyStat, kkk;                                  // keys, switches, toggles, reeds, bare wires
 word   LedGreen=80,LedRed=80;                                  // blink duration (green on pin A0, red on A1)
 byte   imagePORTC= B00000001;                                  // outputs A0,A1 (01 de-synchronise red-green)
 byte   GoodKey;                                                // 1,2,3,4...10      1,2,3,4..10  and so on
 word   set [] = {4,8,16,32,64,128,256,512,1024,2048};          // easy game : pins 2,3,4,5,6,7,8,9,10,11
                
void setup() {                                                  // INITIALIZATION CODE 
  DDRC  |= B00000011;                                           // A0, A1 as output       (pinA0...pinA1) 
  PORTD |= B11111100;                                           // PC7..PC2 with pullups  (pin7....pin2)
  PORTB |= B00001111;                                           // PB3..PB0 with pullups  (pin11...pin8)  
}

void loop() {                                                   // MAIN CODE 
  delay(01);                                                    //
  
  word iii = ((~PIND & 0xFC) | ((~PINB & 0x0F) << 8)); //-------// PORTD AND B (input pins) READING BLOC
  word jjj = KeyStat;                                           // debounce, state, and front detections
  KeyStat  = iii & kkk;                                         // while key is maintained pressed
  KeyDown  = (jjj ^ KeyStat) & KeyStat;                         // when key is just pressed down
  kkk      = iii;                                               // key configuration stored for next use

  if (KeyDown) { //---------------------------------------------// KEY PRESSED TREATMENT BLOC ----------
    GoodKey++;                                                  // first/next key and value to compare
    if (KeyDown == set[GoodKey-1]) LedGreen = 20;               // good choice for this one...green led
    else {LedRed = 60; GoodKey = 0;}                            // error ! red led and start a new game
    if (GoodKey >= 10) {LedGreen=LedRed=80;GoodKey=0;}          // green/red led blinks together, bingo! 
  }                         

  if (LedGreen) LedGreen--; //----------------------------------// BLINKING LEDS TREATMENT BLOC --------
  if (LedRed)   LedRed--;                                       // blinking in progress 
  if (1 == 1)                 imagePORTC ^= B00000011;          // it blinks here, all the time
  if (!LedGreen)              imagePORTC &= B11111110;          // Green OFF at the end of the term
  if (!LedRed)                imagePORTC &= B11111101;          // Red OFF   at the end of the term
  if (!LedGreen && GoodKey)   imagePORTC |= B00000001;          // maintains Green ON while success
  PORTC =                     imagePORTC &  B00000011;          // set pins A0 A1 (LED green & red)
}