You look at your left-over yarns and you just don't know what to do with them. This was a great project to use my half skeins of yarn. Combining colors and solids with varigated yarns worked out - I love it.
So a project like this takes a little thinking out what you want to do and looking at how much yarn you have before you start knitting. I used what I knew would make it across several rows and it worked. I only have a little ball of yarn left of two of the colors which will go into this granny square blanket I have been working on.The other two colors - well they will sit and wait for that next project that gives me the go-ahead to use them in.
On to the next project. Because there is always something on my needles.
Have fun with colors. Explore, you will be glad you did.