Leonardo de Pisa, known as Fibonacci, introduced a sequence of numbers where each number is the sum of the two preceding ones (1, 1, 2, 3, 5, 8, 13...). The ratio between these numbers approaches the 'Golden Ratio' (approx 1.618). Artists and architects have used this proportion for centuries because it is believed to be the most aesthetically pleasing to the human eye. It appears in the proportions of the Parthenon, the composition of the 'Mona Lisa,' and the spirals of shells and galaxies. This 'divine proportion' bridges the gap between mathematics and art, suggesting a fundamental order in the universe that artists strive to capture in their work.