The Solid Triangle, Pyramid of Flame, or Tetrahedron or Fire is the Admission Badge for the Thirty-first Path of Shin in the 3=8 grade of Practicus in the Outer Order. It is an appropriate hieroglyph of fire, representing the simple fire of nature and the hidden or latent fire. It is formed of four triangles, three visible and one concealed, which yet is the synthesis of the rest. The three visible triangles represent Solar Fire, Volcanic Fire, and Astral Fire, while the fourth and basal triangle represents latent heat. Active Fire is Aud, passive Fire is Aub, equilibrated Fire is Aur, while the Hebrew name of Fire itself is Asch.