So using just what I had in my stash I made large pieces of fabric. Then I inserted narrow strips, using just the challenge colors.
Colors so far --
bright yellow
mauve
peach
dusty blue
avocado
ochre
bright - hurt your eyes - orange
This is really turning out to be a really fun project. The colors have been challenging to find in my stash. I really don't want to buy new fabric but I may have to. Ochre, a color I thought I would have very little of, because I don't do brown was not a problem. There were lots of hand dyed experiments in the stash from mixing too many colors together. When you do this you get brown. Dusty blue on the other hand will require a trip to the quilt store. Although I have a lot of blues most are in the periwinkle or turquoise family. But I did get one block done.
Right now the pieces range from 8-15 inches. We will have a total of 15 colors when finished. At some point I will need to make duplicates but I think I will wait to see what the other colors are before I do the narrow inserts.
This is turning out to be something I really like and I expect it will be a queen sized quilt when finished. It will be fun to put the puzzle together and I am looking forward to figuring out the filler pieces which will be surprises.