These are unique for building. But it should be noted that these are smaller and thinner than they seen online. If one takes that into consideration for older, calmer builders, then these are great. These work best with the small grimm counting blocks as the colors match and the size works best for compatibility. They add an interesting element and in all, I am glad we have them.
Our first Grimm’s purchased included these circles and the rainbow set. Amazing! My two year old spent hours playing with the two together. My 5 year old was even creative and used the rings from the circle to build his own ring toss game! Loads of fun, and great for imaginative play.