The sign, as I overstand, is the symbol of the trinity and the universal sign of peace. It has definite masonic significance, as HIM belonged to the African masonic lodge. Also, as Ras C. Liontree pointed out, it is a yogic symbol, as I have often heard that HIM practiced a form of Hindu meditation (I believe that it is written in one of the books written about Him by one of those of the Imperial court). This can be seen in another picture of HIM, in a suit and tie, sitting to one side with His hands on either leg, His fore fingers touching his thumbs...this is classic meditation hand placement.
Also, in Hindu symbolism, the two triangles of the "star of david" have their own significance. The right-side-up triangle is JAH and the upside-down triangle is Humans, thus the point where they overlap is wher JAH dwells within Humans...IanI! In Egypt it signified balance, as well as in Cabbalistic Judaic thought. There is also triangle symbology in Tibetan Buddhist art as well.
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