Kindergarten Mixes Secondary Colors

As I gain experience in teaching art (almost halfway done with my 4th year!), I'm trying to harder to make each assignment by every student a finished piece of art. One thing that really hindered some pieces from being masterpieces in the beginning of my teaching career was all of the white space on the paper! I occasionally fixed that by using colored paper, but now I am really encouraging students to color all the way to the edge of the paper, no matter what the assignment. All of the famous paintings on my wall are painted in completely; there is no "empty space" where the artist didn't paint. So, I'm encouraging my students to do the same! Last year, while teaching kindergarten students to mix secondary colors, they painted a flower vase based on work by Henri Matisse. This year, I had the students use crayons to create a table and wall behind the vase. I think the finished pictures are better, and the students spent a little more time learning which colors are the secondary colors, as they had to find them in their crayon box, as well as mix them out of the primary colors. Here are a few of this year's secondary color flower vases: