S.T.E.M toys help to develop cognitive thinking that includes problem solving skills. his set of 15 geometry building blocks can be stacked in a variety of way by rotating and nesting the pieces - the possibilities are limited only by the imagination. Every block is a solid piece, which means there are no glue, screws or fixtures, so they are very strong and safe for little hands. Made from high quality and durable ABS, our Prism Cubes are scratch-resistant and waterproof.