IJS MODIFICATIONS. 109 



will intersect each other at right angles, as in the 

 following figure. 



Fig. 133. 



Class c. Solid angles replaced by three planes 

 resting on the edges of the cube. 



The series of new figures resulting from this class, 

 would be contained within 24 isosceles triangular 

 planes. 



Class d. Solid angles replaced by six planes. 

 The new figures would be contained within 48 

 triangular planes. 



Class e. Edges replaced by tangent planes. 



The new figure would be the rhombic dodecahedron. 



Plane e on P or P', 135. 



Classy*. Edges replaced by two planes. 



This class would produce a series of four- sided 

 pyramids on the planes of the cube. The planes of 

 the rhombic dodecahedron, and those of the cube, 

 will evidently be the limits of this series. 



