  A Weyl semimetal has Weyl nodes that always come in pairs with opposite
chiralities. Notably, different ways of connection between nodes are possible
and would lead to distinct topologies. Here we identify their differences in
many respects from two proposed models with different vorticities. One
prominent feature is the behaviour of zeroth Landau levels (LLs) under magnetic
field. We demonstrate that the magnetic tunnelling does not always expel LLs
from zero energy because the number of zero-energy modes is linked to the
vorticity of the Weyl nodes, instead of the chirality. Other respects in
disorder effects for weak (anti-)localization, surface Fermi arcs, and
Weyl-node annihilation, are interesting consequences that await future
exploration.
