Split screen vertically. You won't find it in `man screen`

Now I know what `serendipity' means. It's when you are not quite awake, sit at the keyboard, your fingers fumble and you suddenly see that your xterm window where `screen' is running, gets split in two, but not horizontally (one above another), as it should according to the documentation, but vertically (one beside another). I didn't even understand what keys I pressed to get this effect. `man screen' includes only familiar `split' command. It took me some time to google out the answer.

It turns out that this feature was included in `screen' quite some time ago, but somehow nobody cared to describe it in man. Pressing `C-a |' splits the screen in left and right regions. To get rid of one of the regions, use the usual `C-a X' or `C-a S'.