Pat, I would say you can make a single traditional square your theme, like shoo fly, just be prepared for all sorts of variations
I know a lot of people do embroidered squares and applique. so perhaps you would get a row with several shoo fly pieced blocks, but a section of the row could say "Shoo Fly!" with a picture of a fly swatter & fly in cute embroidery.
We have 2 months to do a single row that is 12.5 by 60.5. We have to have our personal starter row done and mailed off to the next person in our group by December 1st. Then we have 2 months to do the row of the quilt that we received on December 1st. This with take quite a long time to finish
I would guess that some groups will go faster than others