1T MODIFICATIONS. 203 



Modifications. 



Class a. Terminal solid angles replaced by tangent 

 planes. 





Class b. Terminal solid angles replaced by three 

 planes resting on the primary planes. 



Class c. Terminal solid angles replaced by three 

 jlanes resting on the primary edges. 



Modifications b, and c, would produce a series of 

 homboids more obtuse than the primary. 



