Overview & background
The task shapes correspond with whether a task is on a plan or unrelated to a plan.
Pin-icon - task on a specific location within a plan
If a task is created directly on a plan, that task is considered to be a geo-tagged task (one that is specific to that location on the plan), and is indicated by a marker pin icon.
Diamond icon - task associated with a plan
Tasks created while viewing a plan, but not placed in a specific spot, are given a diamond icon. These tasks are a great way to describe widespread issues or comments which are relevant to the entire drawing.
Square icon - not affiliated with a plan
Tasks that are created while viewing the Tasks tab (i.e. are not affiliated with a plan) will have a square icon. These signify general work or milestones for the overall project and are not associated with a specific location. These tasks can be later moved onto plan.
To learn more about geo vs non-geo-tagged tasks, please visit the Task Tab article.
Task is associated with a specific location on plan.
Task is associated with a plan, but not a specific location.
Task is not associated with a plan.
Video Tutorial on Creating Tasks
Video Tutorial on Advanced Task Features