Here’s a look at a sample
progress line:

Here’s what the line means.
|
Right-facing peaks (circled in orange) |
Task is ahead of schedule. |
|
Left-facing peaks (circled in blue) |
Task is behind schedule. |
|
Straight line (circled in green) |
Task is on schedule. |
|
Tasks untouched by the progress line
(circled in red) |
Task is in the future and is not affected
by the progress line. |