Here is my art to reconstruct the heraldic flags for each of the twelve tribes of Yisrael.
(Vere, Stein Atle. ©2011. Image: “Heraldry of the Twelve Tribes of Yisrael”. brakha.blogspot.com.)
The medieval Rabanim (Rabbis) רבנים develop these flags in their book of Bamidbar Raba במדבר רבה .
They assign a “symbol” סימן from the Tora תורה for each tribe of Yisrael (Israel) ישראל , to represent it as a heraldic badge for its official “flag” דגל − “banner” מפה , coat of arms, medal, and so on − in addition to the official “color” צבע of each tribe.
It comes out beautiful.
The reconstruction uses the blazons - the technichal rules - of medieval European heraldry, to approximate the images that the medieval Rabanim refer to, as they design the flags.
The color of the 'imperial purple' (of the amethyst) is irregular, but symbolically significant. I treat it as if one of the 'tinctures' in addition to red, green, blue, and black. Example: all hues of red count as the tincture 'red'. Plus, the two 'metals' are gold equating yellow and silver equating white or light gray.
I derive the flag images from historical medieval badges displaying similar images. The 'shoulder' is unusual, but other bodyparts for badges are common, especially head, face, hand, arm, foot, and leg. In context, shoulder fits in. I havent found a badge with an olive 'tree', but olive branches are common.
I strive to make the impression feel appropriate for medieval pagentry.