6 4 3 2 2 22
3 8 2 8 7 54
XXXX XXXX XXXX XXXX YYYY YYYY YYYY YYYY 1uuu uNNE nnnn nnnn nnnn nnnn nnnn nnnn
X - tile number
Y - tile number
u - unused
1 - always set to 1. This ensures that the value can be distinguished from empty positions in an array.
N - bits indicating immediate "neigbours"
E - extended "neighbour" list used
n - bits for "short" neighbour index
Tiles indexed in "short" list (T original tile)
- -
2 1 0 1 2
-2 0 1 2 3 4
-1 5 6 7 8 9
0 10 11 T 12 13
1 14 15 16 17 18
2 19 20 21 22 23