Maricella's pattern of shirt completion is most likely to be rapid shirt completion with a short break after each five completed.
In the given case, Maricella would get $1 for each shirt that she completes sewing and the condition is that every-time she completes sewing 5 shirts she has to dump them into a bin and then she gets paid.
Her remuneration that is, $5 for five shirts is the motivation factor that drives her to work rapidly as possible. And moreover, she would take rest only after sewing 5 complete shirts as she's bound by the fact that she will get paid only if she complete 5 shirts and dumps it into the bin.
Therefore, we can easily come to conclusion that the working pattern of Maricella would be to take short breaks after quickly sewing 5 complete shirts.