Normal sudoku rules apply. Starting from one end of a white line (which end is to be deduced by the solver), the third digit along the line is the sum of the previous two digits and then the following numbers are the sum of their previous two digits. Where the addition results in a number greater than nine, then only the second of the two digits is placed and this number is used for the ongoing additions (eg 52796516 etc). A black dot separates adjacent digits that are in the ratio of 2:1 and a white dot separates adjacent digits that are consecutive.