Three colour square, not in three colours

I started with the pattern "Three color square" by Betty Barnden in the Crochet Stitch Bible, but I am pretty sure the stitches I used in it are not the same. I may have used double trebles and she used trebles, but don't quote me, I haven't got the pattern in front of me. I did this to make it larger so that I wouldn't need a huge border.

This pattern was a challenge initially, I couldn't seem to figure out what she was saying, but then I relaxed, slept on it and it just clicked.
I quite like it.