The Round Robin worked similarly. We started with a centre block, then each month, instructions were posted on the VMQG blog for how many borders to add, how big they were to be, plus a theme (stars, triangles, curves, etc.). Some folks opted to include some fabric they wanted used throughout the quilt, and others didn't.
My starting "block" was a green scrappy square I made using the slab technique outlined in Sunday Morning Quilts. I asked that each month's additions be monochromatic and scrappy, with the colour being up to the contributor.
I was so happy with my quilt that I went home and almost immediately got to work adding a few more borders to increase its size (I added the red and yellow to complete the rainbow, plus the wide black and white border to contain it all).
I quilted it simply, with straight lines about 2" apart using my walking foot, then FMQ'd in between with Christina A Few Scraps' "beads on a string" design from her Craftsy class (more on that in another post).
I wasn't too sure what colour thread to choose since this quilt has ALL THE COLOURS so I chose white Aurifil 50 weight thread and it worked perfectly, I think. The 50 weight means it's nice and fine and it blended surprisingly well.
I chose green for the binding to echo the centre, where it all began. The quilt is 64"x75" before washing - we'll see how much it shrinks up. I entered it in the QuiltCon show, so we'll see whether it's accepted. In any case, I'm looking forward to snuggling under it as the holiday season approaches.