  <> N U L L - I G N O R E D <>

The NUL (^@) character is ignored by Q, except if it immediately follows ^N or
^P. Thus it can be used as a padding character in q macros, to pad a sequence
out to 2 or 4 characters.
 ^N^@ is only valid within a macro, where it causes the macro to "loop" (resume
execution at start of macro).
 ^P^@ inserts a literal NUL. Use with caution.
