I cut the main blocks 12 inches to start with, and I trimmed them to 12 inches after adding the pieced strips.
The quilts I have seen that I like the best are done with solid colors. I was going to use any light blue scraps I liked in my drawer, but they were all too busy, so I did use the only light blue solid I could find. They look gray in the picture but they are a light blue. I just put a ruler on the block at an angle and sliced the square.
I rejoined the pieces after I inserted the strips. This is very fun and about as improv as I get. It will be fun to see all the colors at the end of the year. If I do 2 every month, I will have 20 blocks. But I think I will want it bigger, so some months I may make more than 2 blocks.
I am linking to