Cylinder Block No. 3

Cylinder Block No. 3 holds a row of knobbed cylinders in which the height falls while the diameter grows, so two dimensions change in opposite directions at once. The child lifts each knob with three fingers, compares by eye and returns every cylinder to the single socket that fits it, which means the material corrects the work instead of an adult. It prepares the hand for the pencil and the eye for the Pink Tower and the Brown Stair, from three years.