The latter. What I'd particularly like to know is how to create a line that shares the same vertical space with the next one (for example, the diagonal line below the E on the first row is mostly sharing the vertical space with the top of the "f" in the word "defumador").

Regarding the vertical lines on the left side, I eventually managed to do it via the "Borders and shading" tool, though it still feels like quite clumsy a solution, especially when I need two or more of them.