Thickbock data validation in googlespreadsheet how to return multiple values

I created a googlespreadsheet here: https://docs.google.com/spreadsheets/d/1K5oc6-XcgMTUSCICr9GguxHWkrm1UuMhnzXu9Rn3ngY/edit?usp=sharing

I would like to return values from all the "checked" thickboxes in a single row like the image below.

Can I do this using a formula?