Did a row robin several years ago with 11 others. We had to specify that the rows could be 6" or 9" finished and had to be 54" long. Each of us had a box that included the fabrics we wanted to have used, our theme (hearts, stars, traditional blocks, etc.) and a quilt diary for each person to write in. We had a month to finish the row, then we met for dinner and to pass on the box. We would show all the rows, but the person whose row was being shown had to leave the room. That way, everyone knew what your rows looked like, but you didn't get to see them until the final month. With 12 people, it took a year, then we had a month to sew all the rows together. My theme was months of the year, and I had a sign up sheet that was passed around before the first exchange so that each person could choose a month and there wouldn't be any duplicates. I call it my calendar quilt.