mind reader illusion

[[UEAK]Clowd]

http://www.curiouser.co.uk/illusions/mindreader3.htm

any ideas on how they did this? at first I thought maybe only one number per grid would work for the given equation, but that doesn't seem to be it...

edit: ok nevermind I just noticed that a lot of the numbers have the same letter attached to them. lol.

 

[Morgan C]

Always a multiple of 9.

 

[Jevil]

 

[JBroll]

Always a multiple of 9.

This is most of it. The number will also be at most 81.

(The sum of the digits of the numbers will be either the remainder of the number after division by 9, 9 plus the remainder after division by 9, or 18 if you picked 99. From this, you're guaranteed to be left with a number divisible by 9 between 0 and 81. Notice that all of these numbers will have the same symbol - look at 0 and the numbers on the diagonal between the lower left and upper right corner, since 9-81 lie there.)

Jeff

 

[Metaltastic]

THIS one always fucked with me, I would love to know how they do it!

EDIT: Oh wait, it's practically the same, nevermind But how does "it's always a multiple of 9" explain it?

 

[JBroll]

They give all multiples of nine the same symbol in the first one. If you can describe the second, I can explain it. (I have no Flash.)

Jeff

 

[Jarkko Mattheiszen]

http://artlung.com/words/flash-psychic-proof/

 

[JBroll]

So... exactly what I said in two sentences. Go me.

Jeff

 

[Jarkko Mattheiszen]

Just thought a more detailed explanation could clear it up a little