OK, thanks. The generated launcher shell command generated
includes '-d -i' flags...

so I tried running without those and voila, life.py terminates
normally. Yay. :-)

2nd, I reviewed the order of commands and I saw that
life2.py and mylife.py (the +1 version) did not have a
'done()' or 'mainloop()' as the last line of the program.
I added those, to no effect. Does nothing I can see.
The other turtle commands appear to me to be "ok",
given that the algorithm is different. For example,
clear() used to be done every loop -- to erase the
turtle tracks -- but that is now done just at the start
because only changed cells are updated, and 
new life/new dead are just updated. 

So, 50% solved. It is an interesting problem because
*my* code seems to be working and *python* does
not appear to be working right. 

Thanks for the help. I might try pygame for a gui
instead...this is getting weird.