A draft is a visual and flexible collaborative document format. It looks like a board with juxtaposed active sheets that can expand in all directions.
1. Active sheet
Each active sheet is 1200x wide and 800px high.
2. How active sheets expand
Moving an item somewhere in the draft will activate all the sheets between the first one, where the draft's origin is, and the one where the item is located. It will always form a rectangle.
3. The origin of the draft
The first sheet of a draft, i.e., the one whose upper-left corner corresponds to the origin (0, 0) of the coordinate system, will always remain active.
This system of active sheets is indicative but here to help you organize your draft.