1st Yellow Cylinder

The 1st Yellow Cylinder is a single cylinder from the yellow block of the knobless cylinders, sold on its own. In that material the child grades the cylinders by eye and hand rather than by a knob, sets them out in a series and later combines the yellow block with the other three in patterns. When one piece is missing, the child can no longer complete the whole series and the material loses its built-in control of error. Ordering the exact number puts a replacement back in the same place in the graded set instead of retiring a full block over a single lost piece. For sensorial work with children from three years.