Hierarchies Recapitulated from Part VII: The “Seven” Thrones in In Operibus Sigillo Dei Aemeth by David Richard Jones.
“Although there are a number of hierarchies of spiritual beings in the Sigillum, there are only three sets of letters from which these names are drawn and from these three sets, three principle groups of angelic names, one for each set. The three sets of letters are those of the Circumference, the Septagon or Holy Sevenfold Table and the Isosceles triangles within the Septagon or Mysterious Sevenfold Table.” [via]