Children explore geometric and engineering builds while developing their fine motor, spatial thinking, and problem solving skills through open-ended quality block play with Block Science Unit Blocks Set A. 28 smooth-sanded rubberwood pieces encourage young builders to create buildings, bridges, and structures to complement builds with their Block Science Foundation Set A. Block Science Unit Blocks stimulate young minds with an incomparable experience of traditional block play while providing hours of continuous play. The blocks are sized based on the basic unit block measurement of 1.4″ x 2.8″ x 5.5″ inches.