It was at one of the early Think Tanks, the one where OMG suddenly revealed that BPDM, their process definition meta-language based on, I think, string theory, would be renamed BPMN 2.0, that the intention to support interchange of BPMN graphics was announced. And I recall a spirited barroom discussion with the editor of the BPDM spec, an energetic young Parisian, in which I insisted that graphics portability could never work because each BPMN tool used different sizes and aspect ratios for their activity, gateway, and event shapes, so the coordinates exported from tool A could not possibly be applied to importing tool B.