How to randomize whole blocks and not only 1 design row?
Add the variables ‘block’ (e.g. deck of 8) and ‘design_offset’.
They need to be in the survey as they control the actual random block selection and the offset to jump to the right design row before the start of the main choice experiment.
A good example is tutorial 31 - Blocking
https://surveyengine.com/software/software-tutorials/