BPMN21 — Page 29, Section 7.2.2 - Fork and Join Differentiation

BPMN says that you use a parallel gateway (diamond with a plus in it) to start a sequence of parallel paths, and another AND gateway to end it. The behaviors of these two gateways are different, but they look the same. Suggestion is that the first AND gateway, that starts the parallel split have a thin line, while the gateway at the end which actually waits for multiple inputs will have a thick line. This corresponds to the thin and thick lines around start and end nodes.