Off Topic: Mind trick reader website

[flagger]

Ok this is too weird. Follow the instructions and then click on the crystal ball. I still haven't figured out how it works.

http://www.cyberglass.co.uk/assets/Flash/psychic.swf

[blnony]

Oh my goodness. . . that is toooo weird.
If you figure out how it works, please let me know. Its kinda creepy, but still fun!

[llzink]

Very cool website. I do know how it works. The symbols change every time you try it. It does not matter what number you pick because it will come out to the same symbol. To see how it works pick one number and see symbol and before you click the crystal ball pick more numbers to see if the symbol stays the same. Hope I explained it well enough.
Thanks

[juliasdad]

Yep. It's a cool trick. There are two factors involved:


SPOILERS FOLLOW!!!


1) When you follow the formula, it reduces the number of possibilities from 100 (0-99) to 10 or so. From your original number N, you are instructed to subtract both the singles and tens digit. Consider that once you've subtracted the singles digit, you've now reduced the possibilities by a factor of 10. For example, all numbers originally in the sixties simply become 60. 62 becomes 60. 68 becomes 60. And so on. So now the possibilities are just all the multiples of 10 (i.e. 0, 10, 20, 30, 40, 50, etc.). You also subtract the tens digit; this just changes to a different set of ten choices and does a good job at hiding the pattern. The possibilities are now 0, 9, 18, 27, 36, ... 81.

2) So, obviously, by just assigning the same symbol to each of those ten numbers above, you guarantee that the player will come up with that symbol. But if the player plays it twice, or three times, and always comes up with a "star" symbol, they'll get suspicious. SO; with every play of the game, change all the symbols! Just make sure that 0,9,18, etc. all have the same symbol and that's the answer.

There's a similar, good card trick that's been around for quite a number of years; go [link:trendy.org/magic/interactivemagic.shtml|here] and click on "Mysterious Rabbit 1" (or 2 to play again).

-dan

[KM]

More Spoilers**

I think this is what dan is trying to say just in a more mathematical way

Any two digit number you choose, "xy" is equal to 10*x + y (simply, the number 32 means 3x10 plus 2). So the equation tells you to take your original number and subtract the sum of its digits, which means take 10*x+y-(x+y), whic reduces to 9*x. THerefore, every solution is a multiple of 9, and if you look at the chart, each mulitple of 9 hs the same symbol.

QED