When this shape is bisected along its longest edge two  
     mirrored parts are produced, a kind of SKEW  
     TETRAHEDRON, left and right oriented, like a pair of 
     shoes. This skew shoe can be bisected into two equal parts 
     which are HALF PYRAMIDS, and these are of course again 
     splitable into skew tetrahedra, and we have completed some 
     kind of cycle. 
           Twelve of these half pyramids will form a cube.   
     Taped together along the edges by the right angle, they 
     make a funny toy, that will flex into a lot of interesting shapes.  
     A model in plastic has been on the market for some years. 
     Of course there are other ways to split the cube, for instance,  
     into halves, along a plane, that bisects six zig-zagging 
     adjacent edges around the cube, producing a  
     HEXAGONAL BISECTIONED CUBE. 
     The geometrical proportions of the silver rectangle: 1: V2 
     with a diagonal V3 shows up again and again in these shapes  
     and very clearly emphasizes the close relationship between  
     the cube and the silver rectangle. 
          By all this, nothing new about the cube has been unveiled,  
     but 1 have amused myself in making these shapes by folding  
     only, and it might amuse others, who are foolishly 
     fond of folding. 
                                                                   THOKI YENN. 
                                                                   MARCH 1985. 
 
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