Melencolia I

The picture I saw in National Palace Museum, it was painted by Albrecht Dürer.

The picture is mainly talked about a young and pretty woman sitting there. There are lots of tools around her, like compass, hourglass, and scale. I guess she was thinking a difficult mathmetic question. One feature of this picture is on the top of the right side.

There is a tab with many numbers. To my surprised, the numbers are like the sudoku. Each two numbers that oppposite to the center point, the sum is 17. It's interesting, isn't it?