Thin - and precisely because of good!

What is presented here by some as negative, namely that these cards are very thin cardboard, is just what I like, because so much more fit cards in the box.
The colorful circles for determining the learning success I think for children / students just good because we see his achievement. That may not be necessary for adults, but the main target audience - just children - I think it's great. You can map out different subjects (ie different well controlled vocabulary) mix, mess queries (which indeed is more meaningful than ever just "sort" to practice) and after sorting in accordance with again. My children see then at least a little taste for learning words-practice because it fills them with pride to see how the cards backwards "wander".