I came across this set and two other sets
while browsing the Anker Home Web site. I found them listed under the title Frӧbelgaben on the left side of the page. I do not know the purpose these were designed, but they are cute and one can always use more stones no matter what size. I was surprised to find they were available practically in my own back yard.
This set came from the "Red Hen" Books and Toys: http://store.redhentoys.com/storefront.aspx in Grand Rapids, Michigan. As I live very near Lake St. Clair in Michigan; Grand Rapids in on the other side of the State about a 3 hour drive from my home.
Frӧbelgabe Nr. 3 contains eight 25 x 25 x 25 mm size stones. or in Anker language stone number 1.