Note: Keep in mind that Unstructured Voxel Blocks are a hybrid
between the Unstructured and Voxel block types: the isotropic region is
filled with hierarchical Cartesian cells (i.e. voxel cells) that interface with surface
domains and/or the final T-Rex front. As such, these blocks can contain all of the supported
volume cell types (i.e. tetrahedra, pyramids, prisms, and hexahedra). On the other hand,
Voxel blocks contain only hierarchical Cartesian cells (i.e. voxel cells).