This is the entry level for the WEDGiTS™ building block toy line. Sometimes referred to as square donuts you will find that WEDGiTS™ nest and stack in both vertical and horizontal configurations. When stacked the five basic shapes form into a four-sided pyramid. The perfect symmetry of WEDGiTS™ create a perfect wedging environment where the blocks actually interlock. This five-piece set is a great to be given as a party favor, as an introduction to the multi-dimensional world of geometric relationships, or as a fast solution for lost parts. Designed for 100% compatibility with all WEDGiTS™ Imagination sets. Great for ages 3 years to 103 years!