north: 80
south: 0
east: 100
west: 0
rows: 8
cols: 10
* * * * * * * * * * 
4 6 7 9 10 12 13 15 16 * 
5 7 8 10 11 13 14 16 17 * 
6 8 9 11 12 14 15 17 18 * 
* * * * * * * * * * 
8 10 11 13 14 16 17 19 20 * 
9 11 12 14 15 17 18 20 21 * 
10 12 13 15 16 18 19 21 22 *