All of the 'Enigma' series of photos are of old silver talisman rings made by the Tuareg, the Berber nomads of the Sahara whose faces are always covered with blue veils.

The rings are based on 'magic square' designs but most also incorporate non-numerical magic symbols. Many of the glyphs also look like characters in the Tifinagh alphabet, the writing system derived from ancient Libyco-Berber (found in North African rock carvings).

These rings are mainly sourced from Mali and Niger, where they are worn as magic charms to keep evil at bay. Some say that each ring is designed by the marabout (the spiritual scholar/doctor) to meet the specific needs of its future owner. I've examined over 50 rings and never seen two with the same design, although there clearly are 'families' where particular sets of symbols tend to be found together.

So there ya go.