The most prominent business process notations in use today are BPMN, EPC and BPEL. While all those languages
show similarities on the conceptual level and share similar constructs, the semantics of these constructs and even
the intended use of the language itself are often quite different. As a result, users are uncertain when to use which
language or construct in a particular language, especially when they have used another business process notation
before. In this paper, we discuss the core characteristics of graph-based and block-structured modelling languages
and compare them with respect to their join and loop semantics.