See the following magic trick. http://www.speedyadverts.com/SAEntertainment/html/realmagic4.html
Believe it or not, the lady didn't really read your mind; she is not even a real lady but a computer that used a principle in mathematics called synchronizing words. http://en.wikipedia.org/wiki/Synchronizing_word
That trick was done with 25 flags. I think it would be neat if I could do it with a lot more flags, but at the same time I wouldn't want the spectator to get bored with lots of instructions.
Is there a good way to do this with say 200 flags with only one or two more instructions? How about 1,000 flags?