Thanks, I think I understand now! I didn't grasp "square groups" (not even in the 2.0 demo animation) because the groups that highlight aren't 2x2, they are groups of 5 squares. If that's confusing to people, maybe they could be referred to as "2x2 groups" instead of "square groups" or something. (And/or the actual 2x2 square could be highlighted differently from the bolt when you match, so visually there is a 2x2 group to see.)