This is a magic square effect where spectators freely enter numbers in the main diagonal and you quickly fill out the rest of the numbers producing a perfect magic square.
Alternatively you could perform this the classic way that a spectator calls out a number and you fill in all the numbers to form a magic square. But the effect is stronger if your audience can freely choose not just the sum but several numbers in the square. In a variation Werner shows you how spectators can even select the squares where you should next enter a number during your fill-out sequence.
The method is so simple that when I first read his instructions I couldn't believe that it works. Well, I can guarantee you it does work. If you can add 2 and subtract 3 you are in business with this routine.
Werner also included a presentational variation for a birthday square. Ask the spectator for is age. Enter the age into the center square and then construct a magic square that will have the spectators birth year as the sum.
For more magic square methods from Werner Miller also see E-Z Square 2.
[Please note that this is not the same as Chuck Hickok's Diagonal Magic Square.]
