pub type Position = (usize, usize);
Position is a (row, col) position on a Grid.
For example such table has 4 cells. Which indexes are (0, 0), (0, 1), (1, 0), (1, 1).
┌───┬───┐ │ 0 │ 1 │ ├───┼───┤ │ 1 │ 2 │ └───┴───┘