Pisa seems to have been proud of its native son, medieval mathematician Leonardo Bonacci (c. 1170–c. 1250), known as Fibonacci, as demonstrated by a reference to his famous sequence recently discovered in the marble inlay work of a lunette on the newly restored San Nicola Church on via Santa Maria in Pisa.
Wear and tear on the thirteenth-century church had left the detailing completely illegible. But in the course of the restoration, Peter Armienti, professor of petrology and petrography at the University of Pisa, uncovered the mathematical pattern, spotting the reference in the sizing patterns and relationships of the lunette’s overlapping circles.
Armienti noticed a size-shifting formula that corresponded with the first nine digits of the Fibonacci sequence: 1, 2, 3, 5, 7, 13, 21, 34 and 55. In his opinion, it is a direct reference to Fibonacci or a circle of his close colleagues and students. Armienti, who has published his findings in the Journal of Cultural Heritage, commented, ‘Marble inlay, by its nature, is an ideal platform for charting irrational numbers’.
The discovery is, in his estimation, ‘a precious gift from the past after 800 years of oblivion; we should be grateful for its presence’.