It is shown that every closed
nonempty subset of a polyhedron can be the fixed point set of a suitable self-map if
the polyhedron satisfies a certain connectedness condition. Hence the same is true for
all compact triangulable manifolds with or without boundary. The proof uses
existing results on deformations of polyhedra with a minimum number of fixed
points if the dimension of the polyhedron is at least two, and on self-maps of
dendrites with given fixed point sets if the dimension of the polyhedron is
one.