Rough initial draft. A compilation of suggested contents.

Vertical Arabic

Arabic vertical texts can "be found" in contexts like book-sides, margin-writing etc.,  where we have horizontal text and it's  just rotated left or right. Another context is when Arabic script is mixed with scripts like Chinese or Mongolian which are normally written vertically.

Let's examine Arabic behavior in each situation separately.

Cases for vertical Arabic

Let's start with some pics showing Arabic vertical texts :

• Book sides
  

  

•  Margin writing
  

  

• Cinema hall sign, or alike
  

  

• Tables headers and footers

Todo : find a real life example




•  etc.

Discussion. Use cases, historical examples,  regional variations ...

Text orientation

To discuss :

• Top to bottom vs. bottom to top. Depends on authors, editors ? ...
• The point when Arabic is mixed with LTR scripts. Top to bottom for Arabic means bottom to top for Latin, and vice-versa. So, it may depend on authors/regions or the dominant script of the page. 
• Arabic upright, isolated letters, bottom to top doesn't make sens.
• CSS corresponding properties (writing-mode, text-orientation) and values (upright, vertical-lr/rl, sideways-lr/rl)
• ...

Implementations

What is on CSS, what is on implementation. Current implementations  compared  to  current or common  usages.

Mixing Arabic with CJK...

How vertical Arabic is interacting with other vertically written scripts.