[TazeTSchnitzel]

A horizontally flipped (straight edge on the right) cursor does exist, I think some versions of Microsoft Word use it when editing the left margin of a document or something like this. I don't think it's a standard Windows cursor though.

[anthk]

Linux/BSD just have to use "xsetroot -cursor_name left_ptr".

OFC you can set that graphically, but this way it's universal.

[mixmastamyk]

Also selecting numbered lines in a text editor, say on X.