If you look at the sign in the back, it has the word “for” and a symbol that resembles the clubs symbol on cards. So it makes her think of four of clubs unconsciously. This is what Blain meant by “subliminal messaging.”
As he flips the cards for her to look for one, the cards are flipped at an angle in a way she can't really see them until the last card which he allows her to see by showing more of it. This is how he knows she will pick the four of clubs. 2:02
it's not necessarily the last card, that would be too obvious. it's an old card trick, i remember seeing it on old vhs how to tapes on magic when i was a kid. you just flip the cards really fast except for one that's slightly raised in the middle that you hold onto for about a millisecond longer and it's the only card that sticks in the person's memory.
he made her look at the deck while he flipped all the cards really fast and said think of a card, he simply flipped them all so fast that you couldn't see any of them except for the 4 of clubs because he held that one card slightly longer than all the rest of the cards, it's a very hard thing to pull off without training.
Three am, hour of hell, when the inverted pentagram flashes in the mind, and a satan takes flight. Three am, and a poke on the rib, and warm breath to awake he who has knocked on the forbidden door. Not magic, but magick, and only fools play with it. To hell they will descend.
When David Blaine says "you're looking at it". In the background, the banner has the words "for" as in the #4 and to the left of it was a symbol that looked like a clover which she was thinking about.
He wouldn't be able to count on that trick at all if she had to notice that; watch closely when he riffles through the cards really fast. I don't want to give it away but trust me it's as simple as you might think if you watch that part a few times (and pay attention to the sound).
so everyone knows, ive figured it out when he flipped the deck and told her to remember one of the cards the brain onl rememberd the last card of the deck, when he was flipping it. he put the card there to set it up, since he knew the card number and type he got the sharpy to say that
"He got the sharpie to say that" Well that is the part that clearly deserves the explaining lol. He already had it written on the sharpie so how'd he know (or suggest) she was going to pick the 4 of clubs?