I dig levels in mosaic. The pieces of many heights catch the light and enliven the surface, and I love that. I also dig them literally, since grouting buries the lower pieces and I go on an archaeological dig to find them. People are often surprised by the levels, and intrigued. Once a young woman came into my booth at a craft show, accompanied by a friend who guided her by the elbow. She had a patch over her one eye. She spent a moment investigating the surface of a mosaic with her fingers, and I was all the more glad that there were levels for her to enjoy.