Sapin de Noël / Christmas tree
Électronique / Electronic
555, 4029, 74HC138, UNL2003

4029 (UP Down binary or decade counter)
Pin 9 (0 = Decade, 1 = Binary)
Pin 10 (0 = Down, 1 = UP)
Pin 7 Carry Out  = 1 (over 7 or 15) / Retenue (au-dessus de 7 ou 15)
                        = 0 (from 0 to 7 or 15) / (de 0 à 7 ou 15)

Conteur Binaire / Binary Counter

Conteur Décimal / Decade Counter