BPMN21 — Section 10.2 Clearer separation between conceptual and visual model needed

Description of issue: This section mixes conceptual meta-model statements with visual representation statements. A clearer separation of those concepts is needed.
– p 127 (157 in PDF) "... inclusion of re-usable tasks and processes in the diagram" should be "... invocation of re-usable tasks and other processes from the process"
– p 127 (157 in PDF) "... a process is not a graphical object. Instead, it is a set of graphical objects." A process is neither, it is a container for activities and other entities, all of which have a graphical representation.
– p. 133 (163 in PDF) ff "A task is a rounded corner rectangle" should be "A task is represented by a rounded corner rectangle". This occurs frequently for all task types, so globally change "is a rounded corner rectangle" to "is represented by a rounded corner rectangle"