This set of tactile sensory stones gives children the opportunity to extend their understanding of shape through exploratory play. The ridged and smooth surfaces of the shapes offer children a rich sensory experience, and their vocabulary of shape and comparative language will develop as they talk about what they see and feel. The set includes twelve stones (measuring 2 to 3.2 inches), with two different sizes and thicknesses for each of the six shapes: circle, triangle, square, rectangle, pentagon, and hexagon. Ages 3+.