  In this work we prove a shape theorem for a growing set of Simple Random
Walks (SRWs), known as frog model. The dynamics of this process is described as
follows: There are some active particles, which perform independent SRWs, and
sleeping particles, which do not move. When a sleeping particle is hit by an
active particle, it becomes active too. We prove that the set of the original
positions of all the active particles, rescaled by the elapsed time, converges
to some compact convex set. In some specific cases we are able to identify (at
least partially) this set.
