  The performance of multiple reconfigurable intelligent surfaces (RISs)
receives limited attention in previous studies. This article fills this
research gap by investigating the capabilities of multiple RISs in real-world
networks. We propose a simplified yet highly scalable sandwich architecture for
implementing one-bit unit cells, with the flexibility to accommodate multi-bit
unit cells. To effectively control multiple RISs, we present a cost-effective
remote-controlling scheme and develop a cloud-based RIS management system.
Through a series of four field trials, we demonstrate the effectiveness of
multi-hop routing schemes in establishing reliable links. Our experiments
reveal significant improvements in signal strength and data transmission in
multi-RIS-aided Wi-Fi and commercial 5G networks. Furthermore, we investigate
the power scaling law of RIS-aided beamforming and provide insights into the
roles of the later nodes in multi-hop relay chains.
