I first wrote about this system in a 2006 whitepaper that outlined most of my productivity tools and methods at the time.

Practice (Dash): Undone Action Item — Individual items (action items and ideas) are marked with a dash preceding them. All items, no matter what they are, are therefore treated as items to be processed. (Plus): Done Action Item — If the item is an action item (todo), when the item is complete, a vertical line is drawn through the “dash” thus making it resemble a “plus”. This makes the dashed items stand out quite well despite the fact that the same color pen or pencil may be used. (Right Arrow): Waiting – (i.e. for another action) — Drawing an arrow pointing to the the item denotes that it is something that is waiting on another action to happen or deliverable. (Left Arrow): Delegated — Drawing an arrow pointing to the left of the item denotes that it has been delegated (with a note to whom and the date) . (Triangle): Data Point — Turning the dash into a triangle denotes a data point (a fact or figure you wish to remember for instance). (Circle) — A circle around any of the above means that it has been carried forward, moved to another list or otherwise changed status — i.e. a “Waiting” item has now become an Action Item elsewhere (with a note about where that item has gone). The beauty of this system is that it is all built upon, and extensions of, the original dash. Therefore, it is easy to change items from one state to another (an undone action item to a done one, an undone action item to waiting or delegated) and in the case of an non-dashed item changing completely the item is circled to denote that.