Prefer vertical splits over horizontal

My understanding is that a vertical split results in side-by-side panes
as below.

+----+----+
|    |    |
|    |    |
|    |    |
+----+----+

A horizontal split results in a pane above and below.

+---------+
|         |
+----+----+
|         |
+----+----+
Ignore eww cache