As you can see in my link list, our new book The Microguide to Process Modeling in BPMN is available on Amazon. In chapter three, we developed a list of BPMN shapes that can be confusing or hide details.

In the book we argue for the a clear depiction of process models in BPMN. These shapes, while usefull for very technical requirements, will not help this goal.
Some BPMN shapes might not be very useful in a busines-orientedc scenario. For example, there is a multievent shape for an event triggered by any event type. Because it can be misinterpreted, we do not recommend that you use this type of notation. This is also true with the complex merge gateway. It allows any type of split to merge with one generic shape.

Multi Event

Indicates that multiple events trigger these shapes. We are not talking about starting a process with a multi-event, this pattern is usefull. It is the various intermediate and ends we are concerned with. The implementation relies on a runtime engine to execute script or code, therefore the behavior is completely hidden from the diagram. This is useful if you like to write code, but not as useful if you want to effectively communicate with a diagram. Try using the exclusive event-driven gateway with specific event shapes instead.

Complex Merge

Indicates that there are multiple ways to merge flow paths on this shape. While this may seem like a nice shortcut to solve your merge problems, it may introduce interpretation errors and unpredictable merge behavior. Instead, stick to the rule “if you split with it, merge with it.” You can also try using a subprocess shape to merge paths that don’t seem to match up.

Empty Gateway

According to the BPMN specification, this shape is identical to the exclusive gateway. We don’t recommend using it because you are inviting interpretation errors. Being more explicit is always better for accurate communication.

Event Driven Gateway

This is an older version of the event-driven gateway. There are rules restricting this shape so that all attached intermediate events must be identical. The newer 1.1 version (pentagon instead of six-sided star) allows for any intermediate event combination to be attached.

Link Start Event

Signals that the process starts from another page. This does not make sense because if it’s already started it cannot start here. Use the intermediate (catching) Link event instead.
Link End Event

Signals that the process ends here but can continue on another page. This doesn’t make sense because if the process ends, it cannot continue. Use the intermediate Link event instead (throwing).

Excerpts with permission for ‘MicroGuide to Process Modeling’ by Tom Debevoise and Rick Geneva.