] According to De Pasquale, the circles in the cells are
] nothing but the first numbers of the Fibonacci series, in
] which each number is a sum of two previous: 1, 2, 3, 5.
]
]
] The abacus would then work on a base 40 numbering system.

sounds pretty cool, if unverifiable for the time being.

Incan Counting System Decoded?