There are two param1 files for this demo, called param1.1 and param1.2.

Prior to the first execution of cshot1, param1.1 is copied into
param1.  param1.1 specifies a ray plot of 3 reflections from a dome
(file dome).

For the second execution of cshot1, param1.2 is copied into param1.
This time, cshot1 is instructed to produce data for 3 shots. Neither
the model nor any rays are plotted.  Note how the first three
characters in Records 5 and 9 were left blank in order to prevent the
plotting.

Finally, cshot2 is run and builds the traces from the data output by cshot1.

