  We prove that there exists no branched cover from the torus to the sphere
with degree 3h and 3 branching points in the target with local degrees
(3,...,3), (3,...,3), (4,2,3,...,3) at their preimages. The result was already
established by Izmestiev, Kusner, Rote, Springborn, and Sullivan, using
geometric techniques, and by Corvaja and Zannier with a more algebraic
approach, whereas our proof is topological and completely elementary: besides
the definitions, it only uses the fact that on the torus a simple closed curve
can only be trivial (in homology, or equivalently bounding a disc, or
equivalently separating) or non-trivial.
