-<li><em>Hexahedron (i,j,k)</em>meshing algorithm - 6-sided solids are
- split into hexahedral (cuboid) elements.</li>
+<li><em>Hexahedron (i,j,k)</em> meshing algorithm - solids are
+ split into hexahedral elements thus forming a structured 3D
+ mesh. The algorithm requires that 2D mesh generated on a solid could
+ be considered as a mesh of a box, i.e. there should be six nodes shared
+ by three quadrangles and the rest nodes should be shared by four
+ quadrangles.
+\image html hexa_ijk_mesh.png "Structured mesh generated by Hexahedron (i,j,k) on a solid bound by 16 faces"
+</li>
+