  We introduce diagrams for $m$-cluster categories which we call "horizontal"
and "vertical" mutation fans. These are analogous to the mutation fans (also
known as "semi-invariant pictures" or "scattering diagrams") for the standard
($m=1$) cluster case which are dual to the poset of finitely generated torsion
classes. The purpose of these diagrams is to visualize mutations and analogues
of maximal green sequences in the $m$-cluster category with special emphasis on
the $c$-vectors (the "brick" labels).
