  Recently, the complexity behind manipulations of reflected fields by
metasurfaces has been addressed showing that, even in the simplest scenarios,
non-local response and excitation of auxiliary evanescent fields are required
for perfect field control. Although these solutions theoretically allow to
reflect incident plane waves into any desired direction, actual implementations
are difficult and, in most cases, require extensive numerical optimization of
the metamirror topology. In this work we introduce purely local reflective
metasurfaces for arbitrary manipulations of the power distribution of reflected
waves without excitation of any auxiliary evanescent fields. The reflected
fields of such local metamirror contain only the desired propagating waves. The
method is based on the analysis of the power flow distribution and the
adaptation of the reflector shape to the desired distribution of incident and
reflected fields. As a result, we find that these power-conformal metamirrors
can be easily implemented with conventional passive unit cells.The results can
be used for the design of reflecting surfaces with multiple functionalities and
for waves of different physical nature. In this work, we present the cases of
anomalous reflection and beam splitting, both for acoustic and electromagnetic
waves.
