I love this idea by From the Pond! The mat was made for sorting colored pencils, but I could see myself having my students use it to make sure they don't have more than they need in their art boxes. Also, if they are missing a color, they can tell at a glance which one they need without me having to go through all their crayons. I love the idea that this encourages student responsibility and reinforces color recognition and one-to-one matching. :)