.HGR Family

As I annouced before in my 5th book, (PNT and POT) here are my last group of forms.

This increases the number of families to 9 and the number of forms to about 4700 (1180 for .HGR).
However, one should note that this shape has 2 names. So 4-3-2 is equivalent to 2-5-4 and 7-4-9 to 9-2-7 etc... Please notice why..!
This decreases the original number from 1180 to 590.
These groups have got 3 symmetrical planes.
Certain ones whose first reference number is the same as the last one possesses 2 supplementary symmetrical planes. Ex: 3-5-3 or 5-4-5 or 7-3-7.
These forms possess an interesting peculiarity as they change gradually from a square section to a curved section adding thus the qualities of the stability of a vault with the quality of occlusion of an orthogonal section.
This peculiarity becomes more visible when one uses only half of a volume which turned around the axis Y 45°
This facilitates inlaying a door and also allows grouping these forms according to 3 orthogonal directions.
Their names are based on the specifiations given in the following sheet.