it works by doing this:
pick a symbol at random *THIS IS WHY IT FOOLS PEOPLE BECAUSE THE SYMBOL FOR ALL CORRECT ANSWERS IS THE SAME, HOWEVER IT PICKS A NEW SYMBOL EVERY TIME TO BE THE CORRECT ANSWER*
assign every possible answer TO THE EXACT SAME SYMBOL
does not matter which number you pick. when done correctly you will ALWAYS GET THE SAME (randomly generated, see point 1) SYMBOL because every possible answer is the same symbol. the numbers that are not the symbol were not possible answers.
if you don't believe me, do this
look at the number 63's symbol. click button. repeat 5 times.