The activity is the part of project scaffold which is associated with time. Its purpose is to act as an account of work that has been completed, as well as schedule work that can be completed, and project future expansion. Therefore, the activity is divided into three parts:

The Log
The log begins at the first consultation between the client and the architect and ends at the present. It is an exhaustive account of every decision which initiates an action — as well as completed deliverables, invoices, receipts, time sheets, meetings, telephone calls, e-mail conversations, changes to the project scaffold, code commits, bug reports and any other valuable recordable event that happens over the course of the project.
The Schedule
The schedule begins at the present and goes forward only as far as that which can plausibly be estimated. This includes meetings, conference calls and demonstrations as well as scheduled deliveries of work product.
The Road Map
The road map has two parts: the first begins where the schedule ends until the end of the architect's obligations to the client, depicting the nebulous phases of development. The second proceeds onward to further, parallel maturations of the product once complete. The purpose of this is to demonstrate to the client the long-term value of their investment.

As these elements connect temporally, they can be aggregated within the activity as a time line.