Program observation involves formulating a query about the behavior
  of a program and then observing the program as it executes in order
  to determine the result of the query.  Observation is used in
  software development to track down bugs and clarify understanding of
  a program's behavior, and in software testing to ensure that a
  program behaves as expected for a given input set.  RCL is a
  recursive logic built upon conjunctive global predicates.
  Computational structures of common paradigms such as butterfly
  synchronization and distributed consensus can be expressed easily in
  RCL.  A nonintrusive decentralized algorithm for detecting RCL
  predicates is developed, proven and analyzed for complexity.