Columns can be very important when it comes to content presentation. You have a lot of possibilites, from 2, 3, 4 and 5 columns to combinations of different widths.
All other shortcodes work in the same principle:
one_third - one_third_last
one_fourth - one_fourth_last
one_fifth - one_fifth_last
Other possible combinations are:
one_fourth - three_fourths_last
one_third - two_thirds_last