  Featuring excellent coherence and operated parallelly, ultracold atoms in
optical lattices form a competitive candidate for quantum computation. For
this, a massive number of parallel entangled atom pairs have been realized in
superlattices. However, the more formidable challenge is to scale-up and detect
multipartite entanglement due to the lack of manipulations over local atomic
spins in retro-reflected bichromatic superlattices. Here we developed a new
architecture based on a cross-angle spin-dependent superlattice for
implementing layers of quantum gates over moderately-separated atoms
incorporated with a quantum gas microscope for single-atom manipulation. We
created and verified functional building blocks for scalable multipartite
entanglement by connecting Bell pairs to one-dimensional 10-atom chains and
two-dimensional plaquettes of $2\times4$ atoms. This offers a new platform
towards scalable quantum computation and simulation.
