Purchased these building bricks for my two grandchildren for Christmas--both preschool age, as they enjoy building stuff. They absolutely loved these blocks and they have held up very well for almost 2 years, even though they are made of heavy duty cardboard! They have been used as stepping stones, as well as for building. They do have to be folded into the bricks and it is time consuming, according to my daughter, as there are so many of them. Great gift idea.