Magnetic toy building blocks

Claim 1

IN A HOLLOW POLYGONAL BLOCK DEFINED BY A PLURALITY OF WALLS WHICH ARE JOINED TO ONE ANOTHER AT THE PERIPHERAL EDGES OF SAID WALLS SO THAT EACH WALL CONSTITUTES A FACE OF THE BLOCK, THE IMPROVEMENT WHEREIN AT LEAST ONE WALL OF SAID WALLS COMPRISES: A FIRST SHEET OF NON-MAGNETIC MATERIAL HAVING FIRST AND SECOND OPPOSITELY FACING SURFACES, MEANS DEFINING A RELATIVELY DEEP, WITH RESPECT TO THE THICKNESS OF SAID SHEET, DEPRESSION IN SAID SHEET, SAID DEPRESSION BEING OF GENERALLY CYLINDRICAL SHAPE AND HAVING THE LONGITUDINAL AXIS THEREOF NORMAL TO SAID SURFACES; A SECOND, SUBSTANTIALLY PLANAR SHEET OF NON-MAGNETIC MATERIAL SECURED BY A FIRST SURFACE THEREOF OF SAID FIRST SIRFACE OF SAID FIRST SHEET AND OVERLYING SIAD DEPRESSION; AND A MAGNET LOOSELY DISPOSED IN DEPRESSIONN, SAID MAGNET BEING RETAINED IN SAID DEPRESSION BY SAID SECOND SHEET, SAID MAGNET HAVING A THICKNESS SUBSTANTIALLY SMALLER THAN THE DISTANCE BETWEEN THE FIRST SURFACES OF SAID FIRST AND SECOND SHEETS AND AN EXTENT IN THE DIRECTION PERPENDICULAR TO THE LONGITUDINAL AXIS OF SAID DEPRESSION SMALLER THAN THE DIAMETER OF SAID DEPRESSION WHEREBY SAID MAGNET IS ROTATABLE IN SAID DEPRESSION.