To view this content, you need to install Java from java.com

Fields are either black or not. The games objective is to mark the correct fields black.

There are two shades of gray to denote non-black fields. So you can mark fields as "not black for sure". To mark a field black click on it. More clicks (or right mouse click) will step through the three states.

You can drag the red circles. This selects a "line" of fields on the board (in red). The number on the left labeled sum is the number of fields in the current line that should be black. The number labeled fill is the number of fields in the current line that you have marked black. The goal is to have these numbers coincide on all possible lines. The game tells you if you are done.

Typing a number over the board will restart the game with a board of the size of the i-th prime (0->2, 1->3, 2->5, 3->7 and so on).

If you found a systematic way to solve the puzzle, then you understood the principle of the inverse Radon transform (at least in a finite field setting...:-))

>>for the answer click here.