  The specific rotational alignment of two-dimensional lattices results in a
moir\'e superlattice with a larger period than the original lattices and allows
one to engineer the electronic band structure of such materials. So far,
transport signatures of such superlattices have been reported for graphene/hBN
and graphene/graphene systems. Here we report moir\'e superlattices in fully
hBN encapsulated graphene with both the top and the bottom hBN aligned to the
graphene. In the graphene, two different moir\'e superlattices form with the
top and the bottom hBN, respectively. The overlay of the two superlattices can
result in a third superlattice with a period larger than the maximum period (14
nm) in the graphene/hBN system, which we explain in a simple model. This new
type of band structure engineering allows one to artificially create an even
wider spectrum of electronic properties in two-dimensional materials.
