Unlike Grouping Sequences, where multiple lessons, or pages, or chapters, get grouped into a single lesson, you may want multiple individual lessons in a single day. This would be desired, for example, to assign several lessons in a single day, but have individual scores and times on each lesson.
Grouping Sequences has a special syntax to allow the day's group to have individual lessons.
will produce two individual lessons per day. Note the second asterisk.
Where the group sequence
produces one lesson covering two per day.