Category Archives: Gadgets, Toys, and “Inventions”

A Card “Force” Using Unintuitive Mathematical Odds

“A card force is one of any number of methods used in close-up magic to apparently offer a subject a free or random choice of card, when in fact the magician knows in advance exactly which card will be chosen. This can then be revealed later in the trick.”

Premise: We have a set of three cards, all of which are known to us. We attempt to force a specific card on the unsuspecting participant by instructing them to randomly point at one of three cards, which are all laying face down. Theoretically, they have a one in three chance of picking the correct card randomly. If they point at the desired card, we immediately instruct them to flip it, effectively “forcing” the card on them in one try. If this works on the first try, the trick will be especially impressive. However, if it doesn’t work on the first try, we still have a fall-back method:

If they point at one of the other cards, instead of telling them to flip the card, we pretend that they’re playing a game of elimination and we simply remove the card, instructing them to point again. If they point at the next incorrect card, we instruct them to remove it, leaving one final card: the correct one.

Potential downside: If they point at the desired card on the second step, then the “force” fails,
because when we remove it, the end card will actually be the incorrect one.

Cards used: Ace of Hearts (the desired card), Queen of Clubs, and 8 of Spades

Approximate Results After 2000 Simulations:
Times ended on Ace of Hearts: 1322 (0.661)
Times ended on Queen of Clubs: 339 (0.1695)
Times ended on 8 of Spades: 339 (0.1695)

Click here to run the simulations yourself using javascript

Odds of picking the right card during the first step: 1/3. If incorrect card is chosen on first step, we pretend it’s an elimination game and remove the card, leaving only two cards, the desired card, and the incorrect card. At this point, you might think there is an even 50/50 chance they will choose the correct card, but in reality, the odds of them choosing and eliminating the desired card are still 1/3 because it hasn’t been touched. The odds of them choosing and eliminating the second incorrect card, however, have increased to 2/3. This is unintuitive, but the simulation shows it to be true.

Because of the fact that we know which cards are which, we can effectively double our seemingly low 33% odds all the way to 66% simply by using this card force method.

The only unsolved problem is, how do you handle a dead end where someone chooses the wrong card, and then the right card on the second step?

Drawing a smiley face on the moon

Smiley MoonWhat would you do if you had a billion dollars? I don’t know about you… but I would definitely develop a method to draw a smiley face on the moon. Call me crazy, but can you think of a better legacy to leave behind? Yeah. I didn’t think so.

Think about it. Future generations of mankind would look up in the sky at night, only to see a big smiling face. Wars would cease to exist! How could people even think about fighting with a giant smile in the sky?

Or maybe we could sell the moon one pixel at a time? Like the site did?

Maybe we could use a high powered laser that would burn the dust and turn it black or something… *scratched his head*. What do you think?

Seriously though, what would you do if you walked outside one night and noticed a smiley face on the moon?

Successful Invention #1

One of the things that I always aspired to be when I “grew up” was an inventor. As a child, I would take apart toasters, pencil sharpeners, lawn mowers, and generally anything I could get my hands on that was broken and had some sort of intriguing moving parts. However, while I have come up with a number of concepts of my own over the years, until now there was never any actual follow-through.

Scenario: I have a thermostat in my apartment that I want to control with a schedule. I want to be able to cool down the house at night, but warm it up in the morning so I don’t have such a hard time waking up and getting out of bed. In previous apartment complexes, I was able to use a standard 7 day, programmable thermostat (available from Walmart, Lowes, or your favorite home supply store for around $30-$75). However, the heating system in my apartment complex here in Phoenix uses an old system and is incompatible with virtually all the programmable thermostats out there. I was only able to find one programmable thermostat out there that would work with my apartment’s heating/cooling system, but it didn’t have some of the capabilities that I was looking for. So I am basically limited to manually moving the needle on my thermostat by hand if I want to change the temperature. No programmable scheduling allowed!

Solution: Using a small servo, a mini SSC II controller, and a serial interface to connect it all to my computer, I built a remote controlled thermostat module. The servo is mounted on the wall above the thermostat and a string is connected to the needle. Once I figured out how to send commands to the servo using my computer’s com port, I interfaced it with PHP page on my local web server. I then built a flash-based interface with a draggable temperature slider that would send the proper positioning values to the PHP page. The end result… a thermostat in my living room that can be physically controlled from anywhere in the world over the internet.

Click here to watch a demonstration video clip!
(12 megs in size. Windows Media Player required.)