Whoever wants to understand much must play much. –Gottfried Benn. The Golden Ratio has an interesting property: Its square is only one more than itself. For large numbers, given any Fibonacci number, you can approximate the next Fibonacci number by multiplying the current one by (1+√5)/2, that is F(n+1)≈φF(n).
MS 2913. CALENDAR WITH GOLDEN NUMBERS, FEASTDAYS, OCCUPATIONS OF THE MONTHS AND HOURS OF LIGHT AND DARKNESS, TABLE WITH GOOD AND EVIL DAYS. MS in Norwegian and Latin on vellum, Uvdal, Norway, 1636, 30 ff. (complete), 5,5x5,5 cm. Not bound but plied together to form a book, in its original girdle type leather covered wooden box. www.schoyencollection.com