Square Boston

The squares above are just two of dozens embedded in the sidewalk piazza near the Chinatown Arch in Boston. Are they fossils? Rock carvings? Chinese characters?
The Boston sidewalk squares shown below are definitely Chinese. They were located on the sidewalk leading up to the Chinese arch. The centre portion was scribed granite block, surrounded by ordinary concrete pavers, set in the join of regular poured concrete sidewalk.
The Ottawa Chinatown BIA is considering something similar for the reconstruction of part of the Chinatown sidewalks in 2011.