The thing I was worried about the most turned out to be the easiest! Go figure! How to quilt the tall marble columns was wayyyyy more fun than the repetitious bricks. I used 4 colors of thread on this large column.... Each thread "locked" or keyed in to the adjacent so as to allow for a smooth visual transition. It takes a little planning... i.e. leaving space for the next thread color to lock in to the currently sewn one... but it's not all that big a deal once you get started. Click on any photo for enlarged view.
This lock and key idea came from a long ago painting instructor encouraging painters to link one element of a painting to another. It makes the overall result less fragmented. I think this will do the trick.
It's almost there.... this is admittedly a partial view of this St Antimo's Church Quilt.