What does the key look like?

Under the picture, each color's number (or code), a small circle and the color's name, four to a row (three on a 6 x 9 book). The key text is 12 pt in books for toddlers, kids and seniors, 10 pt in the others. In a black and white book the circle is empty, so the reader can try the pencil in it (a grey swatch would be useless). When the book has colored answers at the back (a color interior), the circle is filled with the color. With the Shapes code, the shape itself stands in the key, without the circle, in a black and white book. The picture is made a little smaller to leave room for the key.