Grid[{{$a_1$, $a_2$, ...}, {$b_1$, $b_2$, ...}, ...}]GridBox.Grid[{{a, b}, {c, d}}]
For shallow lists, elements are shown as a column:
Grid[{a, b, c}]
If the sublists have different sizes, the grid has the number of columns of the largest one. Incomplete rows are completed with empty strings:
Grid[{{"first", "second", "third"},{a},{1, 2, 3}}]
If the list is a mixture of lists and other expressions, the non-list expressions are
shown as rows:
Grid[{"This is a long title", {"first", "second", "third"},{a},{1, 2, 3}}]