The ARD language is defined in a serial fashion and it is very possible
for entries early in the file to be modified by later entries, if they
contain EXCLUDE regions. e.g. a file containing a definition of an
annulus followed by a circle will behave as you would expect, however, if the
annulus and circle are the other way round the circle definition will
probably be completely superceeded by the annulus. At present this
effect is limited to ANNULI, beware that the XSPOKES language definition
contains an annulus. When producing a file containing the ribs definition,
the ribs should be selected first.