Figure 4: Topological characterization of a 5-terminal junction, each contact having a single channel.
From: Multi-terminal Josephson junctions as topological matter

The coloured areas display a nonzero Chern number C12. The boundaries of these areas correspond to the projection of the Weyl singularity lines to the (ϕ3, ϕ4)-plane. In a 3D subspace the curves can be assigned a charge.