# Computations of an old woman

Recently I met a Polish woman who showed me something very interesting. Apparently her mother kept notebooks which she filled with strange calculations, never telling anyone what they were for. From the way she described them to me as notebooks "filled with numbers", I at first privately thought it might be a case of graphomania, but the notebooks look far too organized and purposeful to be the scrawlings of a schizophrenic.

Her mother passed away a few years ago, having never told anyone the purpose of the calculations (she apparently used to dismiss it as "something stupid" when asked, and got annoyed if pressed). Her mother was a high level Bridge player and a trained accountant, and since the word "podatek" (tax) appears on one of the pages, it seems likely that the calculations were something to do with finance, but then you get to the pages that look like this:

It's easy to see some patterns in most of the calculations - some things are obviously sums and products, and there doesn't seem to be anything in there more advanced than basic integer arithmetic. Some of the pages feature dates, and some pages contain lists of Polish words. It's harder to see where the actual numbers come from, and so far I haven't been able to find any hint of the connection between the graphs and the calculations.

Here's a zip file containing all of the notebooks (31.3 MB).

Note: I'm posting this with the permission (in fact, at the request) of the woman's daughter. The notebooks don't appear to contain any personal information (e.g. peoples' full names or bank account information).

• @user1717828 The backstory is real. – Jack M Mar 30 '16 at 14:52
• Yep, I also usually draw some really intricated and complex graphs when calculating my insurance risks. – Narmer Mar 30 '16 at 15:33
• @Narmer Other words on this page are also finance related: wpłat, dopłaty, pożyczki, bank. It's possible that the notebooks were used for different things. – Sleafar Mar 30 '16 at 15:40
• All of the nodes I have look at in the graph contain an even degree. This means it is most likely possible to construct a path which connects all nodes. (Imagine starting at one point with a pen and moving node to node never picking your pen up or repeating an edge). It could be something like a cross-stich pattern, or some other path. Its possible that if you separate the edges that are vertical or horizontal from the ones that are diagonal it could be something. (As someone might do by making some connections on one side of a fabric and other connections on the other side.) – Tony Ruth Mar 31 '16 at 0:26

This is by far not a full answer, rather some preliminary observations. I didn't spent much time on this (yet). I encourage others to build upon these observations, for what they're worth.

The notebooks were definitely multi-purpose. I'll use Nx/Pyy notation for yy-th page (file Page??.jpg) in x-th notebook.

# TO DO lists

There are at least two TO DO ("do zrobienia") lists, one on N2/P90, one on N5/P13. These lists do contain surnames and some nicknames. Some items are labelled as ZUS (Zakład Ubezpieczeń Społecznych — social insurance agency) and Urząd Skarbowy (revenue agency). Fortunately, it seems extremely unlikely to identify the people involved without a lot of auxiliary information.

# Doodles

Given the locations of the drawings, I would interpret them as doodles. Some people like to draw geometric shapes in their idle time (I do!), I wouldn't put too much emphasis on them, nor would I try to find a relation to the calculations.

# Calculations

Probably of more than one kind, given the different templates. This is the main puzzle, as far as I can see.

A significant part of the calculations probably has something to do with accounting. Most sheets have dates, some tables are broken down into months, many numbers are in orders of magnitude consistent with household budgets. Note that there are some relatively high (but not unusual) amounts here and there, e.g. N2/P91 has some kind of month-by-month simulation of operations on a 300 000 capital. It that is PLN (which is likely), it is roughly 70 000 EUR.

Some other pages might be records of some games, although, after a quick browse, I didn't catch a page that would be consistent with recorded bridge scores.