Every card in a Lenormand deck carries a small inset of an ordinary playing card in one corner, and the Tower carries the 6 of Spades.
Why the deck has thirty-six cards
Taken together the insets across the deck make up a complete thirty-six card playing pack, running from the six to the ace in each of the four suits. That is not a correspondence scheme laid over the pictures afterwards. The deck was published in Nuremberg in 1799 as a race game called Das Spiel der Hoffnung, the Game of Hope, generally attributed to Johann Kaspar Hechtel, and the insets meant the same printed sheet could be cut up and used for ordinary card games as well. The pictures were the board and the playing cards were the pack.
What the suit adds
The 6 of Spades belongs to the suit this atlas records under conflict, intellect and hardship. It is a pip card. In playing card cartomancy the numbered cards are generally read as circumstances rather than as people, and the number is read alongside the suit.
Two systems in one deck
A reader who uses the insets is running an older cartomantic system, the reading of an ordinary playing pack, alongside the pictures. The two layers can disagree about a card, and nothing in the deck settles which should win. Many readers ignore the insets entirely and treat them as a leftover of the deck's origin as a game. Both approaches are current, and this atlas records the inset as part of the object rather than as an instruction.