In orthography of the Arabic language, there is a condition where a noun ending with “fat-hatan tanween” (double fat-ha nunation) will have an Alef added to the end to support such tanween, with a few exceptions where Alef would not be needed.
The tanween can be placed over the Alef, but a more preferable and common practice is to place the tanween over the letter preceding the Alef, which would be the actual final letter of the word before adding the supporting Alef, or alternately, to the right of the Alef instead of above it. The first case has been common in the past half a century due to its simple implementation with the typewriter, then with the computer keyboards, while the second case was the more common practice since the earliest examples of Qurans where vowel marks are indicated in the text from the 9th century to the beginning of the 20th century.
I am adding a feature to an Arabic typeface to allow users to place the tanween to the right of the Alef as in the second case above, and I am writing this inquiry to see if you know of any other language written in the Arabic script that uses this writing convention?
Please see attached image where I show the first case on the right side of the image with marks colored black and placed over the Alef. In the center I show the second case where the marks are colored red and placed over the preceding letter. And on the left, I show my preferred placement colored green, just to the right of the Alef. Please note, that although I titled the green position as “correct,” all three options are actually acceptable and attested historically.