Caught my eye about "tav" being 21st letter (from link), 'cause have always thought 22 -- now will have to reconsider. ha.
The image of 'T' as a cross reminds me of the five t's grouped together in the New Testament: 1,2 Thes / 1,2 Tim / Titus, and how they exemplify, for me, the scene at Calvary with the 2 malefactors and 2 thieves.
Enjoying your post -- keep 'em coming! /s/ dux
Dux allows: "It is the glory of God to conceal a thing: but the honour of kings is to search out the matter". Pr25:2