If that may reassure you... not only Pd has messes of uncooked spaghetti going under boxes and stuff. And not only dataflow diagrams have them. This is an example in a data-relational diagram in a database app :
http://www.altova.com/images/landing_page/mapforce_screenshot_large.png
And cooking the spaghetti softens the spaghetti but it's still spaghetti.
OTOH, it would be a lot more readable already if the middle boxes were just placed in proper places...
| Mathieu BOUCHARD ----- téléphone : +1.514.383.3801 ----- Montréal, QC