There are just some colours that I don't use in my artwork. It's not that I don't like them but I just tend to gravitate naturally to some and not others. Ultramarine blue is not one that I choose to use but when I had to think of a colour that had a "U" in it for this round robin page, it came immediately to mind. I thought of the underwater world and the gorgeous blues and greens that are associated with different bodies of water. This is my entry for this week's Crazy Amigo Challenge.