original_query: What are the main differences between B and Z in terms of their focus and implementation ease? What is the most relevant chunk to answer the query?
query: What are the main differences between B and Z in terms of their focus and implementation ease?
answer: Compared to Z, B is slightly more low-level and focuses more on refinement to code rather than formal specification.  This makes it easier to implement a specification written in B than one in Z, due to better tool support. B uses the same language for specification, design, and programming.