[r-t] Decisions / Algorithms for generating the extent

[Alexander Holroyd]

Nice analysis Richard!

Have you posted your list of in-course doubles extents to [r-t]?

For more entertainment, one could search for in-course doubles extents 
that do not come round, in hopes that two such could be joined by a pair 
of different singles to form a 120.  (There is an interesting such 120 at
http://www.math.ubc.ca/~holroyd/comps/o5.txt )

Ander