base 3 sudoku

Each location is defined by 4 digits:

For rows: the first two digits define the row number, the next two define the column. Etc.

== Example ==

So if I have a grid of:

00 01 02, 10 11 12, 20 21 22
10 11 12, 20 21 22, 00 01 02

Then row 2 column 6 is Row 02:21

The first digit chooses which triplet, the second is the location within the triplet. In the above example R02 means that I'm in the 0'th triplet (which is the first one) and the second place in that triplet. This is the 2nd row.

:22 means that along that row I go to the last triplet (2 of 0,1,2) and in it to the middle square in the triplet (1 of 0,1,2).

num(x,y) = x*3 + y + 1;

xy(n) = int((n-1)/3) + (n-1)%3.