Surveys sometime contain "loops," sub-sections of the survey that are repeated several times. This is common in product concept testing and patient case reviews:
Flatten vs stack
There are a few ways that looped data can be represented. One is to "flatten" the data, such that there is one row per respondent, and one column per question per loop:
Another is to "stack" the data such that there is one column per question and one row per respondent per loop:
Protobi can represent both structures.
Which makes the most sense for your survey? That depends on your survey and analysis goals.
Below is a PDF with a more detailed discussion...