* table source
* test of gradients
7
7
* x row
0 1 2 3 4 5 6
* y column
0 0.5 1 1.5 2 2.5 3
* table
1 1 1 1 1 1 1
2 2 2 2 2 2 2
3 3 3 3 3 3 3
4 4 4 4 4 4 4
5 5 5 5 5 5 5
6 6 6 6 6 6 6