  Studying the pathlength dependence of high P_T hadron suppression in
heavy-ion collisions by measuring the dependence of hard hadron production on
the angle phi with the reaction plane in non-central collisions has so far been
one of the most successful tools in constraining the microscopical picture of
leading parton energy loss. With the imminent start of the LHC heavy-ion
program and the possibility of full jet reconstruction, the focus has shifted
to models which are capable of simulating full in-medium parton showers rather
than tracing the leading parton only. Yet, on the level of single inclusive
hadron observables, such shower models need to reproduce the findings of
leading parton energy loss models, in particular they need to reproduce the
correct reaction plane angle dependence of hadron suppression. The aim of this
work is to illustrate at the example of the in-medium shower code YaJEM (Yet
another Jet Energy-loss Model) how pathlength dependence arises in a MC shower
formulation, how it relates to pathlength dependence of leading parton energy
loss and how model results compare with data on the reaction plane dependence
of the nuclear suppression factor R_AA(phi).
