run that by me one more time

Long before Fibonacci popularised the sequences in his book Liber Abaci, however, the sequences had been known to Indian Mathematicians. They had drawn upon the sequences to help them enumerate the number of possible poems of a given length, using short syllables of one-unit duration and long syllables of two-unit duration. The Indian poet/mathematicians knew that you could make a poem of length n by taking a poem of length n-1 and adding a short syllable or a poem of length n-2 and adding a long syllable. Consequently, they figured out that to work out the number of poems of a given length you just had to add the number of poems that were one syllable shorter to the number that were two syllables shorter – the exact rule we use today to define a Fibonacci sequence.