Futility Closet posted a how-to for this neat mathematical card trick by New York magician Henry Christ. It's called All Roads.
Shuffle a deck thoroughly and deal out nine cards in a row, face down. Choose a card, look at it, and assemble the nine cards into a stack face down, with the chosen card at the top. Add this stack to the bottom of the deck.
Now deal cards one at a time from the top of the deck into a pile, face up, counting backward from 10 as you do so. If at some point the card’s rank matches the number said, then begin dealing into a new pile at that point, counting again backward from 10. If you reach 1 without a match occurring, then “close” that pile by dealing a face-down card onto it, and start a new pile.
Keep this up until you’ve created four piles. Now add the values of any face-up cards on top of the piles, count down through the remaining cards until you’ve reached this position, and you’ll find your chosen card.
This works because it always leads to the 44th card in the deck, but it takes some thinking to see this. You can put a sealed deck into a stranger’s hands and direct him to perform the trick himself, with mystifying results.
I am in awe of people who can think of things like this.
David Robinson used the data from the 28,657 people who self-selected to take the Stack Overflow survey to investigate the relationship between programmer pay and the conventions of using either tabs or spaces to mark indents, and found a persistent, significant correlation between using spaces and bringing home higher pay.
It’s the end of an era, sort of: Fraunhofer IIS, the developers of the MP3 audio compression format, announced that they are ceasing their licensing program. In a blog post, spokesman Matthias Rose says that it’s had a good 20-year run and is obsolete. But it’s also true that the decoding patents expired last year, […]
Freddy deBoer writes that he’s been telling the same joke for years about Silicon Valley’s only product, which might be universalized as “At last, a way to verb with nouns on the internet!” But the social-media techopoly is stable, now, and so the venture capitalists have moved on to the three terrible trends that will […]
Despite the upfront cost, electric toothbrushes are much better at removing plaque than those freebies from the dentist’s office. For those who struggle to fill the American Dental Association’s recommended two minutes of brushing time, or anyone with limited dexterity, a sonic toothbrush can give your oral care routine a boost.To keep your chops healthy […]
Learning a new language will give your resume an upgrade, sure, but it will also provide a huge cognitive boost for mental tasks outside of translation and conversation. Bilingual brains have been shown to be better at handling multiple concurrent tasks, and gaining fluency in a new tongue is an amazing way to improve memory, […]
If you struggle to get a good night’s rest, consider replacing your pillows before dropping hundreds on a new mattress. You can give your tired neck a break with a 2-pack of memory foam pillows, available now in the Boing Boing Store.Each of these pillows is stuffed with cooling polyurethane foam that molds to your […]