Double flower of life(that contains the 64 tetrahedron grid)((=)84(vesica piscis)×2=168)=torus=E8(8D 64 tetrahedron grid)((=)168 roots), 21st triangle number=(6×(pointing up)7th triangle number(=168 (roots)))+(3×(pointing down)6th triangle number((=)21)(=63 (roots))).
