  We consider colliding wave packets consisting of hybrid mixtures of
electromagnetic, gravitational and scalar waves. Irrespective of the scalar
field, the electromagnetic wave still reflects from the gravitational wave.
Some reflection processes are given for different choice of packets in which
the Coulomb-like component $\Psi_2$ vanishes. Exact solution for multiple
reflection of an electromagnetic wave from successive impulsive gravitational
waves is obtained in a closed form. It is shown that a succesive sign flip in
the Maxwell spinor arises as a result of encountering with an impulsive train
(i.e. the Dirac's comb curvature) of gravitational waves. Such an observable
effect may be helpful in the detection of gravitational wave bursts.
