Task Flow Arrows
"Flow Arrow" -- Definition:
On these charts, an arrow shows sequencial dependency. The task at the head of the arrow cannot be done unless all the tasks at the base of all the arrows have been completed.
Using this rule while experienced people join to build the flow chart maintains a high degree of confidence that everything needed for the later task has been included, and that no needed task has been missed.
Respecting this rule while managing and tracking project progress, helps maintain a high degree of confidence that everything needed for the project is being done, and that no steps have been missed or skipped.