I saw a tutorial somewhere on this but i don't remember where. It seemed so easy but i can't attempt it until i figure out how to get one of my 4 rufflers to work on one of my 2 machines.
The trick was to ruffle 2 sides of each block and then cut the other sides to match. When you lay them out you alternate the directions of the squares so that a gathered side is against a straight side. But The size of the pieces of fabric depends on how much of a gather you want. I think there would have to be some sort of formula.
I wish i was better at explaining, i can sort of see how i would attempt it but i can't think of good words.
It's on my huge to do list but some other things recently got my attention and bumped it down on the list.