These vividly colored, beautifully crafted 3/4 inch plastic blocks attach smoothly and snuggly in all directions. Create 2 or 3 dimensional pictures, models designs and artwork. Each block has a number of open squares and one square projection for connecting to another block. Each size set comes with a different quantity and type of block and a poster of possible models for copying or to spark the imagination. Terrific product for building fine motor skills, bilateral hand skills, finger/hand strengthening and design copying and motor planning.