! If you wanted to be pointlessly clever, the tick loop can
! instead be implemented as a series of cascading, parallel
! threads mapped over the desired time intervals.
: tick-loop ( n -- )
   0 swap 0.5 <range> [ reverse ] keep zip
      [ first2 seconds sleep
        "This page will self-destruct in %.1f seconds.<br/>"
        sprintf send-chunk ]
   parallel-each ;