Leonardo Pisano known as Fibonacci (Pisa, ~ September 1170 - Pisa, ~1242) was an Italian mathematician, and is known above all for the sequence of numbers identified by him and known, in fact, as the "Fibonacci sequence" - 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89 ... - in each term, apart from the first two, is the sum of the two preceding it.

A peculiarity of the Fibonacci sequence is that the ratio between the successive pairs of terms tends very rapidly to the number 1.61803 ..., known as the golden ratio or golden section. The applications are innumerable: in chemistry, botany, the human body, geometry and nature, economics, computer science, systemic games, art, and music. It is said that Mozart, Debussy, Béla Bartók, Strawinsky, and Stockhausen have used the golden ratio and Fibonacci's sequence. It is also used in modern music, especially in so-called progressive rock (Genesis where Firth of Fifth is all based on golden numbers, Deep Purple in the song Child in Time and Dream Theater in the Octavarium album).

From the suggestion of the Fibonacci series, Peter Wilker has traced an interesting effect that fully exploits the mathematical properties of the Fibonacci sequence.

The version presented here enriches the effect, thanks to an original script, adding an interesting variation that offers the mentalist the possibility of predicting already at the beginning, after only 2 numbers what the final result will be, making the effect stronger.

The effect can be conducted in person or by telephone, without the need for a video connection; in this case, the method is easier because no one can see that the mentalist performs calculations; for in-person performances, the solution proposed by Wilker is simple and effective (you have to multiply a number by 11) you can also use notes and a pen (if you are afraid of not being able to do the calculation in mind). If you do that you will have to justify their use (for example following another effect where it is necessary to use pen and paper); you could also use an assistant, which performs the calculation and provides the result to the performer.

1st edition 2021, PDF 6 pages.
word count: 1743 which is equivalent to 6 standard pages of text