The Petit Lenormand has an unusually well-documented origin for a divinatory system, and the origin is not divinatory.
The Game of Hope
In 1799 a Nuremberg manufacturer named Johann Kaspar Hechtel published Das Spiel der Hoffnung, the Game of Hope, printed by Bieling. It was a race game. Thirty-six numbered cards were laid out in a grid to form a track, players threw dice and moved counters along it, and certain squares carried consequences: the Ship sent you forward, the Coffin sent you back, the Anchor held you where you were.
Hechtel died in 1799, the year it appeared. The game was still being advertised two decades later.
The accompanying leaflet noted that the cards could also be used for fortune-telling. That was a secondary suggestion attached to a boxed game, not a system.
Why thirty-six
The number is not symbolic. Each card carries an inset of a playing card, and the insets make up a complete piquet pack: six through ace in four suits, thirty-six cards, the standard shortened deck of German and French card play.
The deck is a picture-book laid over an ordinary pack, which is why every card in this atlas has a playing-card equivalent recorded against it. Those equivalents are the older layer.
Why the Grand Tableau looks the way it does
The full Lenormand spread lays all thirty-six cards out in rows, most commonly nine across and four down.
That is the game board. The largest and most characteristic spread in the tradition has the shape it has because it inherited the layout of a race track from a Nuremberg toy.
This is not an argument against the method. It is an account of where the method's furniture came from, and it is a good deal more interesting than an invented Egyptian pedigree would have been.