Hi,
After one month of work I ( with help of experts ) have made program
which works = plots Apollonian gasket :
http://maxima-project.org/wiki/index.php?title=File:Apollonian7.png
Some theory also :
http://en.wikibooks.org/wiki/Fractals/Apollonian_fractals
It uses circle Descates theorem.
It is not finished but works.
It is based on lists.
It works , but there is a problem which I do not understand.
All positive curvatures are computed using fp function ( see wikibooks or
src code ),
Most, but not all centers are computed using also fp function.
Some centers, in a one gap, must be computed using fm function.
I do not see a rule which centers need fm, which fp.
Thus function fill_hard_gap is so messy.
Comments are wellcome
I will try to improve it.
Adam