Hi rick,
Thank for your suggestion.
If we try in this way, there are both trial-level random (within individual blocks) and block-level random (across whole runs). And I think this would take much time to do the iteration evaluation procedure. In fact, what I want to make is similar to ordinary ER-design, with only one restriction that the same number of trials for one factor are grouped together.
However, I will try it out. Thank you though, rick!
Best,
Qiuhai