The use of domain-specific languages (DSLs) is a successful technique in the development of complex systems. Indeed, the construction of new DSLs addressing the particular needs of software projects has become a recurrent activity. In this context, the phenomenon of specification cloning has started to appear. Language designers often copy&paste some parts of the specification from legacy DSLs to "reuse" formerly defined language constructs. As well known, this type of practices introduce problems such as bugs propagation, thus increasing of maintenance costs. In this paper, we present Puzzle, a tool that uses static analysis to facilitate the detection of specification clones in DSLs implemented under the executable metamodeling paradigm. Puzzle also enables the extraction specification clones as reusable language modules that can be later used to build up new DSLs.