Robert Herzog e-mailed me to say that the plot was complete
if one used a tektronix 4014 window, so I tried...
(then the 4014 and term options)
% xterm -t -e codonpreference -nopref -bias=gc
This opened a (black and white) X-window in which the full
plot was drawn.
SASS, University of Edinburgh,
Edinburgh, Scotland, U.K.
frank @ sass.sari.ac.uk